upgrade to v1.20 libraries, fixes issue#484 (#507)

Author: jjo

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.13.8 as build
+FROM golang:1.15.15 as build
 ENV GO111MODULE=on
 
 WORKDIR /workspace
@@ -14,6 +14,8 @@ COPY pkg/ pkg/
 COPY proto/ proto/
 COPY Makefile Makefile
 
+# As (generated) proto/service.pb.go is _also_ committed, void the need to install protoc / protoc-gen-go plugin
+RUN touch proto/service.pb.go
 RUN make bin/kiam-linux-amd64
 
 FROM alpine:3.11

go.mod

@@ -8,13 +8,9 @@ require (
 	github.com/coreos/go-iptables v0.3.0
 	github.com/fortytw2/leaktest v1.3.0
 	github.com/golang/protobuf v1.4.3
-	github.com/googleapis/gnostic v0.2.0 // indirect
 	github.com/gorilla/mux v1.7.3
 	github.com/grpc-ecosystem/go-grpc-middleware v1.0.1-0.20190118093823-f849b5445de4
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
-	github.com/howeyc/gopass v0.0.0-20170109162249-bf9dde6d0d2c // indirect
-	github.com/imdario/mergo v0.3.4 // indirect
-	github.com/onsi/ginkgo v1.10.3 // indirect
 	github.com/onsi/gomega v1.7.1 // indirect
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/prometheus/client_golang v1.8.0
@@ -23,16 +19,14 @@ require (
 	github.com/vmg/backoff v1.0.0
 	golang.org/x/net v0.0.0-20201216054612-986b41b23924 // indirect
 	golang.org/x/sys v0.0.0-20201214210602-f9fddec55a1e // indirect
-	golang.org/x/text v0.3.4 // indirect
 	google.golang.org/genproto v0.0.0-20201214200347-8c77b98c765d // indirect
-	google.golang.org/grpc v1.34.0
+	google.golang.org/grpc v1.36.0
+	google.golang.org/grpc/examples v0.0.0-20211020220737-f00baa6c3c84 // indirect
 	google.golang.org/grpc/security/advancedtls v0.0.0-20200204204621-648cf9b00e25
 	google.golang.org/protobuf v1.25.0
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 	gopkg.in/fsnotify.v1 v1.4.7
-	gopkg.in/inf.v0 v0.9.1 // indirect
-	k8s.io/api v0.0.0-20180521142803-feb48db456a5
-	k8s.io/apimachinery v0.0.0-20180515182440-31dade610c05
-	k8s.io/client-go v7.0.0+incompatible
-	k8s.io/kube-openapi v0.0.0-20180629012420-d83b052f768a // indirect
+	k8s.io/api v0.20.0
+	k8s.io/apimachinery v0.20.0
+	k8s.io/client-go v0.20.0
 )