fix: trigger server release workflows on workflow changes (#1939)

Trigger the server-v3 and server-v4 release workflows when their
workflow files change, and ignore deleted changeset files during release
detection.

<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Make server-v3 and server-v4 release workflows run when their own
workflow files change, and prevent false releases by ignoring deleted
changeset files.

- **Bug Fixes**
- Trigger on changes to
`.github/workflows/stagehand-server-v3-release.yml` and
`.github/workflows/stagehand-server-v4-release.yml` on pushes to `main`.
- Use `git diff --diff-filter=d` so removed `.changeset/*.md` files
don’t count as changes.

<sup>Written for commit 3f5911a.
Summary will update on new commits. <a
href="https://cubic.dev/pr/browserbase/stagehand/pull/1939">Review in
cubic</a></sup>

<!-- End of auto-generated description by cubic. -->

Author: monadoid

.github/workflows/stagehand-server-v3-release.yml

@@ -6,6 +6,7 @@ on:
       - main
     paths:
       - .changeset/**
+      - .github/workflows/stagehand-server-v3-release.yml
   workflow_dispatch:
 
 permissions:
@@ -46,7 +47,7 @@ jobs:
           latest_tag="$(git tag -l 'stagehand-server-v3/v*' --sort=-v:refname | head -n 1 || true)"
           changed_files="$(mktemp)"
           if [ -n "${latest_tag}" ]; then
-            git diff --name-only "${latest_tag}"..HEAD -- '.changeset/*.md' > "${changed_files}"
+            git diff --diff-filter=d --name-only "${latest_tag}"..HEAD -- '.changeset/*.md' > "${changed_files}"
           else
             find .changeset -maxdepth 1 -name '*.md' -print | sort > "${changed_files}"
           fi

.github/workflows/stagehand-server-v4-release.yml

@@ -6,6 +6,7 @@ on:
       - main
     paths:
       - .changeset/**
+      - .github/workflows/stagehand-server-v4-release.yml
   workflow_dispatch:
 
 permissions:
@@ -46,7 +47,7 @@ jobs:
           latest_tag="$(git tag -l 'stagehand-server-v4/v*' --sort=-v:refname | head -n 1 || true)"
           changed_files="$(mktemp)"
           if [ -n "${latest_tag}" ]; then
-            git diff --name-only "${latest_tag}"..HEAD -- '.changeset/*.md' > "${changed_files}"
+            git diff --diff-filter=d --name-only "${latest_tag}"..HEAD -- '.changeset/*.md' > "${changed_files}"
           else
             find .changeset -maxdepth 1 -name '*.md' -print | sort > "${changed_files}"
           fi