.github: dependabot: Ignore pydantic-core & consider only pydantic

pydantic and pydantic-core have different release cycles and since a
pydantic release is always locked to a particular pydantic-core
version, a dependabot update to both will cause install conflicts
pretty much every time because dependabot doesn't see transitive
dependency relations.

This patch makes it so that pydantic-core's updates are ignored by
dependabot (because it's a transitive dependency for us) and we're only
going to consider pydantic. This however, will still break installs
because pip-compile needs to be invoked to re-pin this new pydantic
version to a correct pydantic-core version. That is handled by the
newly introduced github dependabot workflow 'dependabot-pipcompile.yml'
introduced in a past patch.

Signed-off-by: Erik Skultety <[email protected]>

.github/dependabot.yml

@@ -19,20 +19,10 @@ updates:
     directory: "/"
     schedule:
       interval: "monthly"
+    ignore:
+      - dependency-name: "pydantic-core"
     groups:
       minor-and-patch:
         update-types:
           - "minor"
           - "patch"
-        exclude-patterns:
-          - "pydantic*"
-
-      # pydantic is a known violator of version updates where they don't release the core backend
-      # with the API library at the same time which holds up other legitimate updates, so group
-      # pydantic deps together
-      pydantic:
-        update-types:
-          - "minor"
-          - "patch"
-        patterns:
-          - "pydantic*"