chore: add repo-metadata.json (googleapis#849)

Author: parthea

.repo-metadata.json

@@ -0,0 +1,14 @@
+{
+    "name": "sqlalchemy-spanner",
+    "name_pretty": "Spanner dialect for SQLAlchemy",
+    "product_documentation": "https://cloud.google.com/spanner/docs",
+    "client_documentation": "https://github.com/googleapis/python-spanner-sqlalchemy",
+    "issue_tracker": "https://issuetracker.google.com/issues?q=componentid:190851%2B%20status:open",
+    "release_level": "stable",
+    "language": "python",
+    "library_type": "INTEGRATION",
+    "repo": "googleapis/python-spanner-sqlalchemy",
+    "distribution_name": "sqlalchemy-spanner",
+    "requires_billing": true,
+    "api_shortname": "sqlalchemy-spanner"
+}