GHA: Force colour output of pre-commit

.github/workflows/lint.yml

@@ -16,7 +16,7 @@
     - uses: actions/checkout@v2
 
     - name: pip cache
-      uses: actions/cache@v1
+      uses: actions/cache@v2
       with:
         path: ~/.cache/pip
         key: lint-pip-${{ hashFiles('**/setup.py') }}
@@ -46,4 +46,6 @@
 
     - name: Lint
       run: tox -e lint
+      env:
+        PRE_COMMIT_COLOR: always
 

tox.ini

@@ -30,3 +30,4 @@
     pre-commit
     check-manifest
 skip_install = true
+passenv = PRE_COMMIT_COLOR