Go: Add static analysis for generated Go bindings

[bact]

Add go vet and staticcheck.

Test will failed as there are few style suggestions from the analysers to be addressed.

See #120

--

These minor issues are also fixed. Mostly about comment lines, missing package name declaration, and code styles.

• ST1000 (package doc missing) - removed a blank line before header to make package doc visible
• ST1021/ST1022 - doc comment must start with a symbol name (type/func)
• ST1023 - var valid bool = true -> var valid = true ("bool" is redundant)
• S1034 - do switch v := x.(type) once instead of re-asserting per case
• S1009 - dropped redundant x != nil && before len(x) > 0
• S1011 - loop-copy -> append(lst, values...)
• S1032 - sort.Sort(sort.StringSlice(...)) -> sort.Strings(...)
• S1005 - for o, _ := range m -> for o := range m

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.

[bact]

Test runs well and detect a number of warnings from S and ST categories:

listproperty.go:73:9: should omit nil check; len() for nil slices is defined as zero (S1009)

shaclobjectset.go:348:10: assigning the result of this type assertion to a variable (switch v := v.(type)) could eliminate type assertions in switch cases (S1034)

encode.go:8:1: at least one file in a package should have a package comment (ST1000)

validator.go:50:1: comment on exported type RegexValidator should be of the form "RegexValidator ..." (with optional leading article) (ST1021)

classes.go:1982:15: should omit type bool from declaration; it will be inferred from the right-hand side (ST1023)

[bact]

@JPEWdev sorry, minor change - commit 0831f23 . I have updated templates it to put {{ disclaimer }} in newline instead, unless the first line could went over.

from

Package {{ package_name }}: {{ disclaimer }}

to

Package {{ package_name }}:
{{ disclaimer }}

Passed locally (only ran on test_golang.py). Will wait for CI to finished the full tests (now including the newly merged C++ static analysis).

[bact]

Tests on Python 3.9 failed not because of our code but because of pyshacl 0.40.0 (released few hours before the previous commit) no longer support Python 3.9 (it uses language construct that Python 3.9 runtime doesn't support).

Fix by pin pyshacl at < 0.40.0.