Merge GH Actions workflows that run tests into a single workflow (#1611)

* Merge GH Actions workflows that run tests into a single workflow
* Configure default_shell when using per_available_shell decorator in tests to make sure the tests are using the right shell
* Add test for per_available_shell decorator does what it's supposed to
* Fix shell tests on Windows by creating an executable for the hello_world package instead of a python script.
* Skip test_build::TestBuild::test_build_custom on Windows since it depends on make and GCC
* Create a python rez package on the fly and use it as a dependency on our test packages. This will hopefully fix issues when there is no system python available.
* Fix linter warnings
* Remove old workflows
* Fix test_deprecation_from_user_config on Windows
* Add python 3.8, 3.9, 3.0 and 3.11 to installation workflow and test with 3.8 in test workflow

---------

Signed-off-by: Jean-Christophe Morin <[email protected]>

.github/workflows/installation.yaml

@@ -21,16 +21,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: 
-          - ubuntu-latest
-          - macos-latest
-          - windows-2019
-        python-version:
-          - '2.7'
-          - '3.7'
-        method:
-          - 'install'
-          - 'pip'
+        os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
+        python-version: ['2.7', '3.7', '3.8', '3.9', '3.10', '3.11']
+        method: ['install' ,'pip']
 
         include:
         # ubuntu
@@ -83,7 +76,7 @@ jobs:
             fi
             pip install --target ~/rez .
         # windows
-        - os: windows-2019
+        - os: windows-latest
           method: install
           REZ_SET_PATH_COMMAND: '$env:PATH="$env:PATH;C:\ProgramData\rez\Scripts\rez"'
           REZ_INSTALL_COMMAND: |
@@ -92,7 +85,7 @@ jobs:
                 conda activate python
             }
             python ./install.py C:\ProgramData\rez
-        - os: windows-2019
+        - os: windows-latest
           method: pip
           REZ_SET_PATH_COMMAND: '[System.Environment]::SetEnvironmentVariable("PATH","$env:PATH;C:\ProgramData\rez\bin"); $env:PYTHONPATH="$env:PYTHONPATH;C:\ProgramData\rez"'
           REZ_INSTALL_COMMAND: |