ci: add support for injecting the latest ops when uv is used (canonic…

…al#1477)

When `uv` is used (as with self-signed-certificates-operator), the
published-charms-tests workflow doesn't know how to inject the latest
version of ops (there's no requirements.txt file).

This PR updates the workflow to look for `uv.lock` and if it exists then
it uses `uv` to change the `ops` source in `pyproject.toml`.

self-signed-certificates-operator doesn't use `uv` to do the install in
`tox` so we have to modify the raw sources list rather than have it be
uv-specific. However, this should work even for projects that do, since
the raw list is the originator of the dependencies - we might need to
re-lock if other projects handle this differently, but we don't for now,
so I've avoided that.

I've tested this manually, and have it manually against the branch
(where it did install ops from my branch).

.github/workflows/published-charms-tests.yaml

@@ -60,7 +60,7 @@ jobs:
           repository: ${{ matrix.charm-repo }}
 
       - name: Install patch dependencies
-        run: pip install poetry~=1.6
+        run: pip install poetry~=1.6 uv~=0.5
 
       - name: Update 'ops' dependency in test charm to latest
         run: |
@@ -77,8 +77,10 @@ jobs:
             echo -e "\ngit+$GITHUB_SERVER_URL/$GITHUB_REPOSITORY@$GITHUB_SHA#egg=ops" >> requirements.txt
           elif [ -e "poetry.lock" ]; then
             poetry add git+$GITHUB_SERVER_URL/$GITHUB_REPOSITORY@$GITHUB_SHA --lock
+          elif [ -e "uv.lock" ]; then
+            uv add --frozen --raw-sources git+$GITHUB_SERVER_URL/$GITHUB_REPOSITORY@$GITHUB_SHA
           else
-            echo "Error: No requirements.txt or poetry.lock file found"
+            echo "Error: No requirements.txt or poetry.lock or uv.lock file found"
             exit 1
           fi