Update ci.yml to ubuntu-20.04 (#503)

Author: Craigacp

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ env:
 jobs:
   quick-build:
     if: github.event_name == 'pull_request' && !contains(github.event.pull_request.labels.*.name, 'CI build')
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     container: centos:7
     steps:
       - name: Install environment
@@ -47,7 +47,7 @@ jobs:
           mvn compiler:compile -Pdev,jdk17 -B -U -e
   check-format:
     if: github.event_name == 'pull_request'
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     container: centos:7
     steps:
       - name: Install environment
@@ -76,7 +76,7 @@ jobs:
         run: |
           mvn spotless:check -Pdev,jdk17 -B -U -e
   prepare:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     outputs:
       stagingRepositoryId: ${{ steps.staging.outputs.stagingRepositoryId }}
     steps:
@@ -93,7 +93,7 @@ jobs:
           echo "::set-output name=stagingRepositoryId::$STAGING_REPOSITORY_ID"
   linux-x86_64:
     if: github.event_name == 'push' || contains(github.event.pull_request.labels.*.name, 'CI build')
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     container: centos:7
     needs: prepare
     strategy: