chore(deps): update github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images commit hash to 420f538 (sourcegraph#3603)

Co-authored-by: Renovate Bot <[email protected]>

Author: sourcegraph-bot

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/pulumi/pulumi v1.12.0
 	github.com/sethgrid/pester v1.1.0
 	github.com/slimsag/update-docker-tags v0.7.0
-	github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-20210806064705-8629716f8e0e
+	github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-20210806085109-420f538102a2
 	golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 // indirect
 	golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898 // indirect
 )

go.sum

@@ -1645,6 +1645,8 @@ github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-2021080602003
 github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-20210806020031-462a422bbc93/go.mod h1:RrAuT1kEkrErj2fmr4f3pPDoBF0ruFBhOSC1yORlv24=
 github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-20210806064705-8629716f8e0e h1:2JH+WxcdXaAYEwi0AwZkS45tBXy3vroO3xG0Qtm40Qg=
 github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-20210806064705-8629716f8e0e/go.mod h1:RrAuT1kEkrErj2fmr4f3pPDoBF0ruFBhOSC1yORlv24=
+github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-20210806085109-420f538102a2 h1:oDVLdAoPoeXg7++eHR7ble5LqxFINI8xLVJVJD8zsRU=
+github.com/sourcegraph/sourcegraph/enterprise/dev/ci/images v0.0.0-20210806085109-420f538102a2/go.mod h1:RrAuT1kEkrErj2fmr4f3pPDoBF0ruFBhOSC1yORlv24=
 github.com/spf13/cast v1.2.0/go.mod h1:r2rcYCSwa1IExKTDiTfzaxqT2FNHs8hODu4LnUfgKEg=
 github.com/spf13/cobra v0.0.3 h1:ZlrZ4XsMRm04Fr5pSFxBgfND2EBVa1nLpiy1stUsX/8=
 github.com/spf13/cobra v0.0.3/go.mod h1:1l0Ry5zgKvJasoi3XT1TypsSe7PqH0Sj9dhYf7v3XqQ=