Fix Weave reference docs workflow to always base new branches on main (#1947)

The create-pull-request action was missing the 'base' parameter, which
meant new branches weren't guaranteed to be created from the latest
main. This caused update-reference-docs branches to be based on stale
commits (e.g., 155 commits behind), resulting in corrupted docs.json
missing integrations and other configuration.

Adding 'base: main' ensures each new PR branch is created fresh from the
latest main commit.

Author: mdlinville

.github/workflows/generate-weave-reference-docs.yml

@@ -133,6 +133,7 @@ jobs:
       uses: peter-evans/create-pull-request@v7
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
+        base: main
         commit-message: "chore: Update reference documentation (Weave ${{ steps.python-sdk.outputs.actual_version || steps.version.outputs.version }})"
         title: "Update Weave reference documentation (Weave ${{ steps.python-sdk.outputs.actual_version || steps.version.outputs.version }})"
         draft: true

.github/workflows/update-service-api.yml

@@ -74,9 +74,10 @@ jobs:
       uses: peter-evans/create-pull-request@v7
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
+        base: main
         commit-message: "chore: Update Service API documentation"
         title: "Update Service API documentation"
-        draft: false
+        draft: true
         body: |
           This PR updates the Service API documentation based on the latest OpenAPI specification.
           

.github/workflows/update-training-api.yml

@@ -72,9 +72,10 @@ jobs:
       uses: peter-evans/create-pull-request@v7
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
+        base: main
         commit-message: "chore: Update Training API documentation"
         title: "Update Training API documentation"
-        draft: false
+        draft: true
         body: |
           This PR updates the Training API documentation based on the latest OpenAPI specification.