Update Cockroach DB Database Dump to use SHOW CREATE ALL TABLES

[muya]

Description

Command "dump" is deprecated, cockroach dump only supports --dump-mode=schema in v21.1. cockroach dump will be removed in v21.2.

More details are in this issue: cockroachdb/cockroach#54040

Additionally, a warning is popping up when one runs migrate up or migrate down against a cockroach DB; sample output:

[POP] 2021/08/16 10:13:57 info - 0.0929 seconds
Command "dump" is deprecated, cockroach dump only supports --dump-mode=schema in v21.1. 
Please use SHOW CREATE ALL TABLES moving forward.
cockroach dump will be completely removed in v21.2.
For details, see: https://github.com/cockroachdb/cockroach/issues/54040
[POP] 2021/08/16 10:13:58 info - dumped schema for...

I think that the change should be made here:

pop/dialect_cockroach.go

Line 198 in 4c1da2d

func (p *cockroach) DumpSchema(w io.Writer) error {

I'm happy to take a stab at it if no one is working on it already.

Steps to Reproduce the Problem

1. Create and execute a migration against a cockroach database

Expected Behavior

• Database migration executes successfully without the deprecation warning

Actual Behavior

• Database migration executes successfully with the deprecation warning above

Info

Please precise your OS, the Pop version and if you're using Pop through Buffalo.

Pop version: v5.3.0 (using through Buffalo)
Using on macOS (11.3.1)

[aeneasr]

#679