Added 2 repositories to java main MD (#3962)

Author: asafm

content/en/docs/languages/java/_index.md

@@ -30,6 +30,12 @@ OpenTelemetry Java consists of the following repositories:
   Provides helpful libraries and standalone OpenTelemetry-based utilities that
   don't fit the express scope of the OpenTelemetry Java or Java Instrumentation
   projects. For example, JMX metric gathering.
+- [semantic-conventions-java](https://github.com/open-telemetry/semantic-conventions-java):
+  Java implementation of
+  [OpenTelemetry Semantic Conventions](/docs/specs/semconv/). For example,
+  `ResourceAttributes.SERVICE_NAME`.
+- [opentelemetry-proto-java](https://github.com/open-telemetry/opentelemetry-proto-java):
+  Java bindings for the [OpenTelemetry Protocol (OTLP)](/docs/specs/otlp/).
 
 ### Components
 

static/refcache.json

@@ -3487,6 +3487,10 @@
     "StatusCode": 200,
     "LastSeen": "2024-01-18T19:37:01.211191-05:00"
   },
+  "https://github.com/open-telemetry/opentelemetry-proto-java": {
+    "StatusCode": 200,
+    "LastSeen": "2024-02-12T10:07:03.426176991Z"
+  },
   "https://github.com/open-telemetry/opentelemetry-proto/#maturity-level": {
     "StatusCode": 200,
     "LastSeen": "2024-01-18T19:37:06.679199-05:00"
@@ -3763,6 +3767,10 @@
     "StatusCode": 200,
     "LastSeen": "2024-01-30T06:01:12.185293-05:00"
   },
+  "https://github.com/open-telemetry/semantic-conventions-java": {
+    "StatusCode": 200,
+    "LastSeen": "2024-02-12T10:07:03.116391658Z"
+  },
   "https://github.com/open-telemetry/semantic-conventions-java/releases": {
     "StatusCode": 200,
     "LastSeen": "2024-01-30T15:25:06.008653-05:00"