test(readme): count README_id.md with the other READMEs (#1482)

A seventh README outside READMES is covered by no count test, which is how
README_es.md went stale before it was added. MANIFEST.in never listed
README_es.md either; both localized READMEs now ship in the sdist.

MANIFEST.in

@@ -5,6 +5,8 @@ include README_zh.md
 include README_ja.md
 include README_ko.md
 include README_ar.md
+include README_es.md
+include README_id.md
 include pyproject.toml
 include Dockerfile
 include docker-compose.yml

agent/tests/test_readme_counts.py

@@ -52,6 +52,7 @@ READMES = (
     "README_ko.md",
     "README_ar.md",
     "README_es.md",
+    "README_id.md",
 )
 
 # Feature badges in the order they appear in every README. Each entry is the