CI: pin actions by SHA

This eliminates the possibility of a tag being changed under
us.

Author: tacaswell

.envrc

@@ -0,0 +1 @@
+export FOO=foo

.github/workflows/lint.yml

@@ -17,7 +17,7 @@ jobs:
         run: pip3 install flake8
 
       - name: Set up reviewdog
-        uses: reviewdog/action-setup@v1
+        uses: reviewdog/action-setup@e04ffabe3898a0af8d0fb1af00c188831c4b5893 # v1
 
       - name: Run flake8
         env:
@@ -39,4 +39,4 @@ jobs:
         uses: actions/setup-python@v3
 
       - name: ansible-lint
-        uses: reviewdog/action-ansiblelint@v1
+        uses: reviewdog/action-ansiblelint@5b8ca4b12dcbcdf63d4739dacd90609abafe8924 # v1