Dependencies need updating (back-end)

[msorens]

Describe the issue

As no one has been actively updating the Go dependencies for at least several months now, some or all of them probably need to be updated to stay current.

Some of these may be simple, some not. Depending on the effort, may want to have a separate PR for each such update.

Quoting from HOW_TO_MAINTAIN_A2.md:

There is no central place to check on all dependencies.
The following, though, lists some of the key Golang dependencies--this is NOT a complete list by any mean.
One can set up a "watch" on each of these repositories to be automatically notified of new releases that can then be scheduled as technical debt items to be done in a timely fashion.

• https://github.com/golang/go/releases
• https://github.com/grpc/grpc-go/releases
• https://github.com/golang/protobuf/releases
• https://github.com/open-policy-agent/opa/releases
• https://github.com/grpc-ecosystem/grpc-gateway/releases
• https://github.com/golang/protobuf/protoc-gen-go/releases
• https://github.com/stretchr/testify/releases
• https://github.com/lib/pq/releases
• https://github.com/dexidp/dex/releases
• https://github.com/nginx/nginx/releases

Note that some of these may be pinned for various reasons; those reasons should be re-examined periodically to see if the issue requiring the pinning can be or has been resolved. Example: at the time of writing, dex is pinned at 2.19.0 as indicated here:

automate/go.mod

Lines 132 to 133 in 4b6d536

	// https://github.com/dexidp/dex/issues/1578
	replace github.com/dexidp/dex => github.com/ryancragun/dex v2.19.0-incompatible+incompatible

To Reproduce

NA

Expected behavior

System still runs correctly after update.

Aha! Link: https://chef.aha.io/epics/SH-E-437