ci: Fix issue that cause the step for creating a GitHub release to exit prematurely.

The patch makes the shell code independent of the  setting.

Author: seifertm

.github/workflows/main.yml

@@ -199,16 +199,13 @@ jobs:
       run: |
         TAG_NAME="${GITHUB_REF#refs/tags/}"
 
-        gh release view "${TAG_NAME}" >/dev/null
-        RELEASE_EXISTS=$?
-        if [ $RELEASE_EXISTS -ne 0 ]; then
-          gh release create "${TAG_NAME}" \
-            --title "pytest-asyncio ${TAG_NAME}" \
-            --notes-file release-notes.md \
-            --draft \
-            $( [ "${PRERELEASE}" = "true" ] && echo "--prerelease" ) \
-            dist/*
-        fi
+        gh release view "${TAG_NAME}" >/dev/null && echo "Release already exists. Exiting." && exit 0
+        gh release create "${TAG_NAME}" \
+          --title "pytest-asyncio ${TAG_NAME}" \
+          --notes-file release-notes.md \
+          --draft \
+          $( [ "${PRERELEASE}" = "true" ] && echo "--prerelease" ) \
+          dist/*
 
   publish-test-pypi:
     name: Publish packages to test.pypi.org