Added SCRAM-SHA-256 support

[jwnl88]

Fixes issue #776 as far as I can tell. These changes allow us to use SCRAM-SHA-256 authentication on the clusters we're running.

[Neustradamus]

Linked to:

• State of Play scram-sasl/info#1

[sgotti]

@jwnl88 Thanks for the PR.

Can you also update the tests (since this impacts also pg_hba logic) to also test that everything works using this new auth method? (I'll just add another flavor of TestFailover in tests/integration/ha_test.go that uses the new auth method).

Also the documentation should be updated.

[jwnl88]

@jwnl88 Thanks for the PR.

Can you also update the tests (since this impacts also pg_hba logic) to also test that everything works using this new auth method? (I'll just add another flavor of TestFailover in tests/integration/ha_test.go that uses the new auth method).

Also the documentation should be updated.

@sgotti Yes, I would like to update the tests + documentation, so this PR can be merged. However, I did run into some errors while trying to run the tests (with ./test).

Does the test script currently fail on the master branch, or did I do something wrong?

(on the master branch)
$ ./test
Running tests...
Checking gofmt...
gofmt checking failed:
./internal/timer/timer_linux.go
./internal/timer/timer_fallback.go

Then I fixed this with gofmt:

$ gofmt -w ./internal/timer/timer_linux.go
$ gofmt -w ./internal/timer/timer_fallback.go

And ran the test script again:

$ ./test                                      
Running tests...
Checking gofmt...
Checking govet...
go: downloading github.com/gofrs/uuid v4.2.0+incompatible
Checking govet -shadow ...
shadow: internal error: package "fmt" without types was imported from "github.com/sorintlab/stolon/internal/common"