chore: housekeeping leftovers from the Codacy cleanup

- Delete posegraph.py, a 2020 prototype in the repository root that nothing
  uses: it imports the deprecated UVertex, has a stub method and debug prints,
  and needs itertools.pairwise (Python 3.10) in a package that supports 3.9.
  The Robotics Toolbox has the real PoseGraph.
- examples/create_json.py: pop('dgoal', None) instead of a bare except.
- Pin the two remaining third-party GitHub Actions to commit SHAs with the
  version in a comment, as RTB did in petercorke/robotics-toolbox-python#892:
  codecov/codecov-action v7.1.1 and dependabot/fetch-metadata v3.1.0.  They are
  the commits that @v7 and @V3 point to today, so what runs is unchanged.
  GitHub's own actions/* stay on tags, and Dependabot updates a pinned SHA with
  its comment.
- Ignore build/ as well as docs/build and dist/.

Part of #23.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Author: petercorke

.github/workflows/ci.yml

@@ -76,7 +76,7 @@ jobs:
           pytest --cov=pgraph --cov-report=xml:coverage.xml
           coverage report
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v7
+        uses: codecov/codecov-action@303a32d7a59b442fa8d48b6a1cc6825c09c847a5  # v7.1.1
         with:
           files: ./coverage.xml
           verbose: true

.github/workflows/dependabot-auto-merge.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
       - name: Dependabot metadata
         id: metadata
-        uses: dependabot/fetch-metadata@v3
+        uses: dependabot/fetch-metadata@25dd0e34f4fe68f24cc83900b1fe3fe149efef98  # v3.1.0
         with:
           github-token: "${{ secrets.GITHUB_TOKEN }}"
 

.gitignore

@@ -1,3 +1,4 @@
+build/
 docs/build
 dist/
 *.code-workspace

examples/create_json.py

@@ -15,10 +15,7 @@
     del info['y']
     del info['dbne']
     del info['utmzone']
-    try:
-        del info['dgoal']
-    except:
-        pass
+    info.pop('dgoal', None)  # not every place has one
     info['utm'] = [info['utm'][0] / 1000, info['utm'][1] / 1000]
 
 routes = []