Fix tox lint command (#623)

* Fix tox lint command

- Move apt-get install command to github actions to run on an ubuntu
  system only. This keeps tox.ini cross-platform and enabled to run on
  non-ubuntu systems locally.
- Add `-y` flag to apt-get install command so it does not wait for
  configuration on CI.

* Downgrade pylint to 2.9.x

* Add pip cache to github actions cache

Author: owais

.github/workflows/test.yml

@@ -44,8 +44,10 @@ jobs:
         # Preserves .tox directory between runs for faster installs
         uses: actions/cache@v2
         with:
-          path: .tox
-          key: v2-build-tox-cache-${{ env.RUN_MATRIX_COMBINATION }}-${{ hashFiles('tox.ini', 'gen-requirements.txt', 'dev-requirements.txt') }}
+          path: |
+            .tox
+            ~/.cache/pip
+          key: v4-build-tox-cache-${{ env.RUN_MATRIX_COMBINATION }}-${{ hashFiles('tox.ini', 'gen-requirements.txt', 'dev-requirements.txt') }}
       - name: run tox
         run: tox -f ${{ matrix.python-version }}-${{ matrix.package }} -- --benchmark-json=${{ env.RUN_MATRIX_COMBINATION }}-benchmark.json
       - name: Find and merge benchmarks
@@ -94,12 +96,17 @@ jobs:
           python-version: 3.9
       - name: Install tox
         run: pip install -U tox
+      - name: Install libsnappy-dev
+        if: ${{ matrix.tox-environment == 'lint' }}
+        run: sudo apt-get install -y libsnappy-dev
       - name: Cache tox environment
         # Preserves .tox directory between runs for faster installs
         uses: actions/cache@v2
         with:
-          path: .tox
-          key: v2-misc-tox-cache-${{ matrix.tox-environment }}-${{ hashFiles('tox.ini', 'dev-requirements.txt', 'gen-requirements.txt', 'docs-requirements.txt') }}
+          path: |
+            .tox
+            ~/.cache/pip
+          key: v4-misc-tox-cache-${{ matrix.tox-environment }}-${{ hashFiles('tox.ini', 'dev-requirements.txt', 'gen-requirements.txt', 'docs-requirements.txt') }}
       - name: run tox
         run: tox -e ${{ matrix.tox-environment }}
       - name: Ensure generated code is up to date

.python-version

@@ -0,0 +1 @@
+3.9.5

dev-requirements.txt

@@ -1,4 +1,4 @@
-pylint~=2.6
+pylint<2.10
 flake8~=3.7
 isort~=5.6
 black>=19.3b0,==19.*

tox.ini

@@ -345,7 +345,6 @@ deps =
   httpretty
 
 commands_pre =
-  sudo apt-get install libsnappy-dev
   python -m pip install {toxinidir}/opentelemetry-python-core/opentelemetry-api
   python -m pip install {toxinidir}/opentelemetry-python-core/opentelemetry-semantic-conventions
   python -m pip install {toxinidir}/opentelemetry-python-core/opentelemetry-instrumentation[test]