[VOL-5222] - Upgrade golang version for VOLTHA jobs

.gitreview
VERSION
----------
  o post-release tasks.  Repository tagged and banched.
  o Add missing newlines at EOF.
  o go.mod syntax does not allow *-dev suffix so update
    master VERSION from v5.5.0-dev to v5.5.0.  Community
    can introduce a dev version when needed.

go/*.pb.og
vendor/*.go
-----------
  o invoke make mod-update to regenerate go.sum and friends.
  o lint clenaups: find . -name '*.go' -print | xargs -n1 gofmt -s -e -w

Change-Id: I3da80c0ce5600679b388e309bfa4702f1ec3212b
diff --git a/vendor/google.golang.org/grpc/metadata/metadata.go b/vendor/google.golang.org/grpc/metadata/metadata.go
index 3604c78..f6ce5c8 100644
--- a/vendor/google.golang.org/grpc/metadata/metadata.go
+++ b/vendor/google.golang.org/grpc/metadata/metadata.go
@@ -41,10 +41,11 @@
 // New creates an MD from a given key-value map.
 //
 // Only the following ASCII characters are allowed in keys:
-//  - digits: 0-9
-//  - uppercase letters: A-Z (normalized to lower)
-//  - lowercase letters: a-z
-//  - special characters: -_.
+//   - digits: 0-9
+//   - uppercase letters: A-Z (normalized to lower)
+//   - lowercase letters: a-z
+//   - special characters: -_.
+//
 // Uppercase letters are automatically converted to lowercase.
 //
 // Keys beginning with "grpc-" are reserved for grpc-internal use only and may
@@ -62,10 +63,11 @@
 // Pairs panics if len(kv) is odd.
 //
 // Only the following ASCII characters are allowed in keys:
-//  - digits: 0-9
-//  - uppercase letters: A-Z (normalized to lower)
-//  - lowercase letters: a-z
-//  - special characters: -_.
+//   - digits: 0-9
+//   - uppercase letters: A-Z (normalized to lower)
+//   - lowercase letters: a-z
+//   - special characters: -_.
+//
 // Uppercase letters are automatically converted to lowercase.
 //
 // Keys beginning with "grpc-" are reserved for grpc-internal use only and may