feat: split versions.txt to independently release the Beam IO (#766)

* Update release_level to GA.

* Split versions.

* Revert changes to release track.

Co-authored-by: Manu Menzella <menzella@google.com>
Co-authored-by: Tianzi Cai <tianzi@google.com>

pubsublite-beam-io/pom.xml

@@ -11,7 +11,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.cloud</groupId>
   <artifactId>pubsublite-beam-io</artifactId>
-  <version>0.17.1-SNAPSHOT</version><!-- {x-version-update:google-cloud-pubsublite:current} -->
+  <version>0.17.1-SNAPSHOT</version><!-- {x-version-update:pubsublite-beam-io:current} -->
   <packaging>jar</packaging>
   <name>Pub/Sub Lite IO</name>
   <url>https://github.com/googleapis/java-pubsublite</url>

versions.txt

@@ -1,4 +1,5 @@
 # Format:
 # module:released-version:current-version
 
-google-cloud-pubsublite:0.17.0:0.17.1-SNAPSHOT
+google-cloud-pubsublite:0.17.0:0.17.1-SNAPSHOT
+pubsublite-beam-io:0.17.0:0.17.0:0.17.1-SNAPSHOT