Update to edition 2021 on master (#3028)

Objective
During work on #3009 I've found that not all jobs use actions-rs, and therefore, an previous version of Rust is used for them. So while compilation and other stuff can pass, checking markup and Android build may fail with compilation errors.

Solution
This PR adds `action-rs` for any job running cargo, and updates the edition to 2021.

Author: YohDeadfall

.github/workflows/ci.yml

@@ -125,6 +125,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
       - uses: actions/cache@v2
         with:
           path: |
@@ -255,6 +258,9 @@ jobs:
     if: always()
     steps:
       - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
       - name: Install alsa and udev
         run: sudo apt-get update; sudo apt-get install --no-install-recommends libasound2-dev libudev-dev
         if: runner.os == 'linux'

.github/workflows/dependencies.yml

@@ -23,6 +23,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
       - name: Install cargo-deny
         run: cargo install cargo-deny
       - name: Check for security advisories and unmaintained crates
@@ -32,6 +36,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
       - name: Install cargo-deny
         run: cargo install cargo-deny
       - name: Check for banned and duplicated dependencies
@@ -41,6 +49,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
       - name: Install cargo-deny
         run: cargo install cargo-deny
       - name: Check for unauthorized licenses
@@ -50,6 +62,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
       - name: Install cargo-deny
         run: cargo install cargo-deny
       - name: Checked for unauthorized crate sources

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "bevy"
 version = "0.5.0"
-edition = "2018"
+edition = "2021"
 categories = ["game-engines", "graphics", "gui", "rendering"]
 description = "A refreshingly simple data-driven game engine and app framework"
 exclude = ["assets/**/*", "tools/**/*", ".github/**/*", "crates/**/*"]

benches/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "benches"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [dev-dependencies]
 criterion = "0.3"

crates/bevy_app/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "bevy_app"
 version = "0.5.0"
-edition = "2018"
+edition = "2021"
 description = "Provides core App functionality for Bevy Engine"
 homepage = "https://bevyengine.org"
 repository = "https://github.com/bevyengine/bevy"

crates/bevy_asset/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "bevy_asset"
 version = "0.5.0"
-edition = "2018"
+edition = "2021"
 description = "Provides asset functionality for Bevy Engine"
 homepage = "https://bevyengine.org"
 repository = "https://github.com/bevyengine/bevy"

crates/bevy_audio/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "bevy_audio"
 version = "0.5.0"
-edition = "2018"
+edition = "2021"
 description = "Provides audio functionality for Bevy Engine"
 homepage = "https://bevyengine.org"
 repository = "https://github.com/bevyengine/bevy"

crates/bevy_core/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "bevy_core"
 version = "0.5.0"
-edition = "2018"
+edition = "2021"
 description = "Provides core functionality for Bevy Engine"
 homepage = "https://bevyengine.org"
 repository = "https://github.com/bevyengine/bevy"

crates/bevy_derive/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "bevy_derive"
 version = "0.5.0"
-edition = "2018"
+edition = "2021"
 description = "Provides derive implementations for Bevy Engine"
 homepage = "https://bevyengine.org"
 repository = "https://github.com/bevyengine/bevy"

crates/bevy_derive/src/enum_variant_meta.rs

@@ -21,7 +21,7 @@ pub fn derive_enum_variant_meta(input: TokenStream) -> TokenStream {
     let indices = 0..names.len();
 
     TokenStream::from(quote! {
-        impl #impl_generics #bevy_util_path::EnumVariantMeta for #struct_name#ty_generics #where_clause {
+        impl #impl_generics #bevy_util_path::EnumVariantMeta for #struct_name #ty_generics #where_clause {
             fn enum_variant_index(&self) -> usize {
                 match self {
                     #(#struct_name::#idents {..} => #indices,)*