go.mod: remove more replace rules

[thaJeztah]

• follow-up to go.mod: go.etcd.io/etcd/server/v3 v3.5.4 #3092
• subset of go.mod: go.etcd.io/etcd/server/v3 v3.5.5 #3085

go.mod: remove replace for google.golang.org/grpc

Moving the comment to warn people when updating.

go.mod: remove replace for github.com/golang/protobuf

it was no longer replacing anything

go.mod: remove replace for google.golang.org/protobuf

it was no longer replacing anything.

docker/docker is already on v1.28.0, and all looks to be working fine.

go.mod: google.golang.org/genproto v0.0.0-20210821163610-241b8fcbd6c8

remove replace for google.golang.org/genproto

full diff: googleapis/go-genproto@81c1377...241b8fc

go.mod: go.etcd.io/etcd/client/pkg/v3 v3.5.5

[thaJeztah]

Looks like a flaky test? Some other parts of that test were disabled in #2137

time="2022-11-23T10:05:19Z" level=error msg="update failed" error="task kcpea42oo4wa6vb9xvqqyu4lb was already shut down when reached by updater (state: SHUTDOWN)" task.id=k9vzsok88psz952rlf8h0ims5
time="2022-11-23T10:05:19Z" level=error msg="update failed" error="task n6s3jixbxjk4nz8gf4hsumaj4 was already shut down when reached by updater (state: SHUTDOWN)" task.id=j1w3hwkw5idey8xptbf0a9yjv
--- FAIL: TestUpdaterRollback (3.90s)
    --- FAIL: TestUpdaterRollback/continue/spec_version_set (1.64s)
        update_test.go:272: service was updated
        update_test.go:337: 
            	Error Trace:	update_test.go:337
            	            				update_test.go:26
            	Error:      	Not equal: 
            	            	expected: "image2"
            	            	actual  : "image1"
            	            	
            	            	Diff:
            	            	--- Expected
            	            	+++ Actual
            	            	@@ -1 +1 @@
            	            	-image2
            	            	+image1
            	Test:       	TestUpdaterRollback/continue/spec_version_set

[thaJeztah]

Thanks! Bringing this one in; one with the next one 😓 😅