CI: miscellaneous cleanups (#8073)

## Problem
There are a couple of small CI cleanups that seem too small for dedicated PRs

## Summary of changes
- Create release PR with the title that matches the title in the description
- Tune error message for disallowing `ubuntu-latest` to explicitly
mention what to do
- Remove junit output from pytest, we use allure instead

.github/actions/run-python-test-set/action.yml

@@ -183,8 +183,7 @@ runs:
 
         # Run the tests.
         #
-        # The junit.xml file allows CI tools to display more fine-grained test information
-        # in its "Tests" tab in the results page.
+        # --alluredir saves test results in Allure format (in a specified directory)
         # --verbose prints name of each test (helpful when there are
         # multiple tests in one file)
         # -rA prints summary in the end
@@ -193,7 +192,6 @@ runs:
         #
         mkdir -p $TEST_OUTPUT/allure/results
         "${cov_prefix[@]}" ./scripts/pytest \
-          --junitxml=$TEST_OUTPUT/junit.xml \
           --alluredir=$TEST_OUTPUT/allure/results \
           --tb=short \
           --verbose \

.github/workflows/actionlint.yml

@@ -36,15 +36,16 @@ jobs:
           fail_on_error: true
           filter_mode: nofilter
           level: error
-      - run: |
+
+      - name: Disallow 'ubuntu-latest' runners
+        run: |
           PAT='^\s*runs-on:.*-latest'
-          if grep -ERq $PAT .github/workflows
-          then
+          if grep -ERq $PAT .github/workflows; then
             grep -ERl $PAT .github/workflows |\
             while read -r f
             do
               l=$(grep -nE $PAT .github/workflows/release.yml | awk -F: '{print $1}' | head -1)
-              echo "::error file=$f,line=$l::Please, do not use ubuntu-latest images to run on, use LTS instead."
+              echo "::error file=$f,line=$l::Please use 'ubuntu-22.04' instead of 'ubuntu-latest'"
             done
             exit 1
           fi

.github/workflows/release.yml

@@ -52,13 +52,15 @@ jobs:
       env:
         GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
       run: |
+        TITLE="Storage & Compute release ${RELEASE_DATE}"
+
         cat << EOF > body.md
-          ## Storage & Compute release ${RELEASE_DATE}
+          ## ${TITLE}
 
           **Please merge this Pull Request using 'Create a merge commit' button**
         EOF
 
-        gh pr create --title "Release ${RELEASE_DATE}" \
+        gh pr create --title "${TITLE}" \
                      --body-file "body.md" \
                      --head "${RELEASE_BRANCH}" \
                      --base "release"
@@ -91,13 +93,15 @@ jobs:
       env:
         GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
       run: |
+        TITLE="Proxy release ${RELEASE_DATE}"
+
         cat << EOF > body.md
-          ## Proxy release ${RELEASE_DATE}
+          ## ${TITLE}
 
           **Please merge this Pull Request using 'Create a merge commit' button**
         EOF
 
-        gh pr create --title "Proxy release ${RELEASE_DATE}" \
+        gh pr create --title "${TITLE}" \
                      --body-file "body.md" \
                      --head "${RELEASE_BRANCH}" \
                      --base "release-proxy"