Build: Use Github environment files instead of deprecated set-output before 2023-05-31

[hoffie]

The set-output command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Many build steps show this warning during autobuild jobs. Need to check other jobs as well. Some warnings might be related to third-party repos. #2936 fixes one such instance.

.github/workflows/autobuild.yml:            echo "::set-output name=build_all_targets::${1}"
.github/autobuild/android.sh:    echo "::set-output name=artifact_1::${artifact}"
.github/autobuild/ios.sh:    echo "::set-output name=artifact_1::${artifact}"
.github/autobuild/linux_deb.sh:    echo "::set-output name=artifact_1::${artifact_1}"
.github/autobuild/linux_deb.sh:    echo "::set-output name=artifact_2::${artifact_2}"
.github/autobuild/windows.ps1:    echo "::set-output name=artifact_1::${artifact}"
.github/autobuild/get_build_vars.py:    print("::set-output name={}::{}".format(varname, varval))
.github/autobuild/mac.sh:    echo "::set-output name=macos_signed::true"
.github/autobuild/mac.sh:    echo "::set-output name=artifact_1::${artifact}"

Adding to 3.10.0 milestone for now, but feel free to drop it if it is not done at release done.