Fail-fast in unsupported environments

https://github.com/pypa/gh-action-pypi-publish/pull/230#discussion_r1632406604

Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

action.yml

@@ -93,6 +93,12 @@ branding:
 runs:
   using: composite
   steps:
+  - name: Fail-fast in unsupported environments
+    if: runner.os != 'Linux'
+    run: |
+      >&2 echo This action is only able to run under GNU/Linux environments
+      exit 1
+    shell: bash -eEuo pipefail {0}
   - name: Reset path if needed
     run: |
       # Reset path if needed