chore: add enumeration data type to .repo-metadata.json (#510)

Adds a standard enumeration of library types in .repo-metadata.json

Author: Neenu1995

.repo-metadata.json

@@ -1,16 +1,17 @@
 {
-  "name": "speech",
-  "name_pretty": "Cloud Speech",
-  "release_level": "ga",
-  "language": "java",
-  "repo": "googleapis/java-speech",
-  "repo_short": "java-speech",
-  "distribution_name": "com.google.cloud:google-cloud-speech",
-  "client_documentation": "https://googleapis.dev/java/google-cloud-speech/latest/",
-  "transport": "grpc",
-  "issue_tracker": "https://issuetracker.google.com/savedsearches/559758",
-  "requires_billing": false,
-  "api_id": "speech.googleapis.com",
-  "product_documentation": "https://cloud.google.com/speech-to-text/docs/",
-  "api_description": "enables easy integration of Google speech recognition technologies into developer applications. Send audio and receive a text transcription from the Speech-to-Text API service."
-}
+    "name": "speech",
+    "name_pretty": "Cloud Speech",
+    "release_level": "ga",
+    "language": "java",
+    "repo": "googleapis/java-speech",
+    "repo_short": "java-speech",
+    "distribution_name": "com.google.cloud:google-cloud-speech",
+    "client_documentation": "https://googleapis.dev/java/google-cloud-speech/latest/",
+    "transport": "grpc",
+    "issue_tracker": "https://issuetracker.google.com/savedsearches/559758",
+    "requires_billing": false,
+    "api_id": "speech.googleapis.com",
+    "product_documentation": "https://cloud.google.com/speech-to-text/docs/",
+    "api_description": "enables easy integration of Google speech recognition technologies into developer applications. Send audio and receive a text transcription from the Speech-to-Text API service.",
+    "library_type": "GAPIC_AUTO"
+}