fix: fix some base32 parsing issues by using go standard library instead of regex

[jamesatkin-myndup]

Fixes Or Enhances

Some strings were failing to be parsed by the previous RegEx based validation. This now uses the Go base32 module (part of the standard library) to more reliably decode the field.

Make sure that you've checked the boxes below before you submit PR:

• Tests exist or have been written that cover this particular change.

@go-playground/validator-maintainers

[coveralls]

coverage: 74.3% (+0.009%) from 74.291%
when pulling 14dc595 on jamesatkin-myndup:master
into a947377 on go-playground:master.

[coveralls]

coverage: 74.297% (+0.006%) from 74.291%
when pulling c17835f on jamesatkin-myndup:master
into a947377 on go-playground:master.

[nodivbyzero]

LGTM

Here are the benchmarks:

goos: darwin
goarch: arm64
pkg: github.com/go-playground/validator/v10
cpu: Apple M1
BenchmarkRegexValidation-8   	 3 077 074	       360.4 ns/op	       0 B/op	       0 allocs/op
PASS
ok  	github.com/go-playground/validator/v10	1.932s

vs.

goos: darwin
goarch: arm64
pkg: github.com/go-playground/validator/v10
cpu: Apple M1
BenchmarkDecodingValidation-8   	 9 891 073	       121.9 ns/op	      48 B/op	       3 allocs/op
PASS
ok  	github.com/go-playground/validator/v10	2.586s

[zemzale]

One less regex is a win in my books. LGTM