Update canonical/charming-actions action to v2.6.0 (#482)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/lib-check.yaml

@@ -38,7 +38,7 @@ jobs:
           tox run -e build-wrapper
           mv requirements-last-build.txt requirements.txt
       - name: Check libs
-        uses: canonical/charming-actions/check-libraries@2.4.0
+        uses: canonical/charming-actions/check-libraries@2.6.0
         with:
           credentials: "${{ secrets.CHARMHUB_TOKEN }}"
           github-token: "${{ secrets.GITHUB_TOKEN }}"