[Go] add version to attribution headers (#606)

Add a version file that contains the current tagged version.

Also add a test for googleai.
It's harder to test vertexai because it uses gRPC.

Also ran `go mod tidy`.

go/go.mod

@@ -14,6 +14,8 @@ require (
 	github.com/google/uuid v1.6.0
 	github.com/invopop/jsonschema v0.12.0
 	github.com/jba/slog v0.2.0
+	github.com/lib/pq v1.10.9
+	github.com/pgvector/pgvector-go v0.2.0
 	github.com/wk8/go-ordered-map/v2 v2.1.8
 	github.com/xeipuuv/gojsonschema v1.2.0
 	go.opentelemetry.io/otel v1.26.0
@@ -24,6 +26,7 @@ require (
 	golang.org/x/exp v0.0.0-20240318143956-a85f2c67cd81
 	google.golang.org/api v0.188.0
 	google.golang.org/protobuf v1.34.2
+	gopkg.in/yaml.v2 v2.4.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -49,9 +52,7 @@ require (
 	github.com/googleapis/enterprise-certificate-proxy v0.3.2 // indirect
 	github.com/googleapis/gax-go/v2 v2.12.5 // indirect
 	github.com/kr/text v0.2.0 // indirect
-	github.com/lib/pq v1.10.9 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
-	github.com/pgvector/pgvector-go v0.2.0 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
 	go.opencensus.io v0.24.0 // indirect
@@ -68,5 +69,4 @@ require (
 	google.golang.org/genproto/googleapis/api v0.0.0-20240701130421-f6361c86f094 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240708141625-4ad9e859172b // indirect
 	google.golang.org/grpc v1.64.1 // indirect
-	gopkg.in/yaml.v2 v2.4.0 // indirect
 )