chore: group remaining dependabot updates with catch-all pattern

Add an 'other-dependencies' group with a wildcard pattern to catch
all packages not already matched by a specific group. This reduces
individual PRs for ungrouped packages like requests, idna, attrs,
cryptography, etc. into a single grouped PR.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: gavinbarron

.github/dependabot.yml

@@ -22,6 +22,9 @@ updates:
       flit:
         patterns:
           - "*flit*"
+      other-dependencies:
+        patterns:
+          - "*"
   - package-ecosystem: github-actions
     directory: "/"
     schedule: