Update module cenkalti/backoff to v4

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/amoghe/go-crypt v0.0.0-20191109212615-b2ff80594b7f
 	github.com/bbrks/wrap/v2 v2.5.0
 	github.com/cenkalti/backoff v2.2.1+incompatible
+	github.com/cenkalti/backoff/v4 v4.1.0
 	github.com/coreos/go-systemd/v22 v22.1.0
 	github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594
 	github.com/go-asn1-ber/asn1-ber v1.5.3
@@ -16,13 +17,16 @@ require (
 	github.com/gorilla/handlers v1.5.1
 	github.com/lunixbochs/struc v0.0.0-20200707160740-784aaebc1d40
 	github.com/miscreant/miscreant.go v0.0.0-20200214223636-26d376326b75
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/openzipkin/zipkin-go v0.2.5
+	github.com/pierrec/lz4 v2.0.5+incompatible // indirect
 	github.com/prometheus/client_golang v1.9.0
 	github.com/russross/blackfriday/v2 v2.1.0
 	github.com/theckman/go-flock v0.8.0
 	github.com/tstranex/u2f v1.0.0
 	go.opencensus.io v0.22.5
 	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad
+	golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421 // indirect
 	golang.org/x/sync v0.0.0-20201207232520-09787c993a3a
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 )

go.sum

@@ -36,6 +36,7 @@ github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kB
 github.com/casbin/casbin/v2 v2.1.2/go.mod h1:YcPU1XXisHhLzuxH9coDNf2FbKpjGlbCg3n9yuLkIJQ=
 github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
 github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
+github.com/cenkalti/backoff/v4 v4.1.0/go.mod h1:scbssz8iZGpm3xbr14ovlUdkxfGXNInqkPWOWmG2CLw=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/cespare/xxhash/v2 v2.1.1 h1:6MnRN8NT7+YBpUIWxHtefFZOKTAPgGjpQSxqLNn0+qY=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
@@ -45,6 +46,7 @@ github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGX
 github.com/cockroachdb/datadriven v0.0.0-20190809214429-80d97fb3cbaa/go.mod h1:zn76sxSg3SzpJ0PPJaLDCu+Bu0Lg3sKTORVIj19EIF8=
 github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd/go.mod h1:sE/e/2PUdi/liOCUjSTXgM1o87ZssimdTWN964YiIeI=
 github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk=
+github.com/coreos/go-systemd v0.0.0-20180511133405-39ca1b05acc7 h1:u9SHYsPQNyt5tgDm3YN7+9dYrpK96E5wFilTFWIDZOM=
 github.com/coreos/go-systemd v0.0.0-20180511133405-39ca1b05acc7/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/go-systemd/v22 v22.1.0 h1:kq/SbG2BCKLkDKkjQf5OWwKWUKj1lgs3lFI4PxnR5lg=
 github.com/coreos/go-systemd/v22 v22.1.0/go.mod h1:xO0FLkIi5MaZafQlIrOotqXZ90ih+1atmu1JpKERPPk=