New `negative-positive` checker and minor changes

What's Changed

Checkers

• add new checker: negative-positive by @ccoVeille in #78
• go-require: require-error: support HTTP handlers by @Antonboom in #90
• require-error: ignore assertion in bool expr by @Antonboom in #89
• useless-assert: support bool ops by @Antonboom in #91

Other

• build(deps): bump golang.org/x/tools from 0.18.0 to 0.19.0 by @dependabot in #74
• Add links in CONTRIBUTING.md by @ccoVeille in #77
• README: notice about "fixing with golangci-lint" by @Antonboom in #85
• build(deps): bump golangci/golangci-lint-action from 4 to 5 by @dependabot in #87
• build(deps): bump golang.org/x/tools from 0.19.0 to 0.20.0 by @dependabot in #86
• introduce helpers_*.go files by @Antonboom in #92

New Contributors

• @ccoVeille made their first contribution in #77

Full Changelog: v1.2.0...v1.3.0