Update Go to 1.16.7

go1.16.7 (released 2021-08-05) includes a security fix to the net/http/httputil
package, as well as bug fixes to the compiler, the linker, the runtime, the go
command, and the net/http package. See the Go 1.16.7 milestone on the issue
tracker for details:

https://github.com/golang/go/issues?q=milestone%3AGo1.16.7+label%3ACherryPickApproved

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

dockerfiles/Dockerfile.e2e

@@ -1,4 +1,4 @@
-ARG GO_VERSION=1.16.6
+ARG GO_VERSION=1.16.7
 
 # Use Debian based image as docker-compose requires glibc.
 FROM golang:${GO_VERSION}-buster