Ignore packages by pattern

This release adds the ability to configure glob patterns to ignore unwrapped errors returned by functions contained in packages that match the glob pattern.

Below is an example configuration.

# An array of glob patterns which, if any match the package of the function
# returning the error, will skip wrapcheck analysis for this error. This is
# useful for broadly ignoring packages and/or subpackages from wrapcheck
# analysis. There are no defaults for this value.
ignorePackageGlobs:
- encoding/*
- github.com/pkg/*