chore(internal/librariangen): bump gapic-generator-go to 0.55.0 (#13345)

refs: googleapis/gapic-generator-go#1668

Author: quartzmo

internal/librariangen/Dockerfile

@@ -64,7 +64,7 @@ ENV PROTOC_VERSION=25.7
 ENV GO_PROTOC_PLUGIN_V1_VERSION=1.5.4
 ENV GO_PROTOC_PLUGIN_V2_VERSION=1.35.2
 ENV GO_GRPC_PLUGIN_VERSION=1.3.0
-ENV GAPIC_GENERATOR_VERSION=0.54.0
+ENV GAPIC_GENERATOR_VERSION=0.55.0
 ENV STATICCHECK_VERSION=2023.1.6
 
 # Set up a home directory for the non-root user that will be running this container.