* refactor: remove `gotest.tools`
* remove all references to `gotest.tools` and replace it with
`github.com/stretchr/testify` which was originally used for tests
* bump `golangci-lint` version
* add `depguard` and `importas` to prevent import of unwanted packages
* add custom schema and information about config since
schemastore.org has broken schema for `golangci-lint` config
* fix: handle more error cases