[VOL-1866] Changed module dependency to v12.0.0 of k8s client-go and v1.15.4 of k8s api/apimachinery in sync with other voltha components

Had to use pseudo-version corresponding to v12.0.0 of k8s client-go
because golang proxy is no longer serving the modules not complying
to Semantic Import Versioning rules including client-go v12.0.0.
Refer to https://github.com/kubernetes/client-go/issues/631 and
https://github.com/golang/go/issues/33558

Change-Id: I2e558bab7f0702f230761319eb5392a7d0532ea3
diff --git a/vendor/golang.org/x/text/unicode/bidi/bracket.go b/vendor/golang.org/x/text/unicode/bidi/bracket.go
index 601e259..1853939 100644
--- a/vendor/golang.org/x/text/unicode/bidi/bracket.go
+++ b/vendor/golang.org/x/text/unicode/bidi/bracket.go
@@ -12,7 +12,7 @@
 
 // This file contains a port of the reference implementation of the
 // Bidi Parentheses Algorithm:
-// http://www.unicode.org/Public/PROGRAMS/BidiReferenceJava/BidiPBAReference.java
+// https://www.unicode.org/Public/PROGRAMS/BidiReferenceJava/BidiPBAReference.java
 //
 // The implementation in this file covers definitions BD14-BD16 and rule N0
 // of UAX#9.
@@ -246,7 +246,7 @@
 // assuming the given embedding direction.
 //
 // It returns ON if no strong type is found. If a single strong type is found,
-// it returns this this type. Otherwise it returns the embedding direction.
+// it returns this type. Otherwise it returns the embedding direction.
 //
 // TODO: use separate type for "strong" directionality.
 func (p *bracketPairer) classifyPairContent(loc bracketPair, dirEmbed Class) Class {