Disable Sonar scanning until it has been set up.

I tried setting this up some time ago, but was interrupted part way through,
and it isn't obvious how to resume the setup.  Deal with it later.

.github/workflows/tests.yml

@@ -26,8 +26,8 @@ jobs:
         run: pytest --cov=. --cov-config=.coveragerc --cov-report xml:coverage.xml
       - name: Track master branch
         run: git fetch --no-tags https://$GITHUB_ACTOR:${{ secrets.GITHUB_TOKEN }}@github.com/$GITHUB_REPOSITORY +refs/heads/main:refs/remotes/origin/main
-      - name: SonarCloud scan
-        uses: sonarsource/sonarcloud-github-action@master
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
+#      - name: SonarCloud scan
+#        uses: sonarsource/sonarcloud-github-action@master
+#        env:
+#          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+#          SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}