Release v2.0.0

[grounded042]

Work for v2 should be done via PRs against the v2 branch. Once we have tackled all of the issues / PRs from the v2 milestone we can do a final review / verification via this PR before officially releasing.

Description

In this release we’ve addressed some long-standing asks and made some major improvements:

• Replaceable JWT validation - you can now bring your favorite JWT package to validate tokens by ensuring it conforms to a simple interface. We provide two implementations for two different JWT packages.
• We now support a custom error handler.
• Under the hood we clone the http.Request instead of a shallow copy in order to better support reverse proxies.
• We now support extracting JWTs from cookies.
• We now store the JWT information using a non-string context key to conform to Golang best practices.
• A caching provider for JWKS is now provided to help you with rate limits from your identity provider.
• We’ve switched errors to use github.com/pkg/errors to provide better error context. If you’re not familiar with the package, don’t worry as it adheres to the error interface.

[codecov-commenter]

Codecov Report

Merging #75 (66a443b) into master (d600c10) will increase coverage by 45.58%.
The diff coverage is 91.45%.

@@             Coverage Diff             @@
##           master      #75       +/-   ##
===========================================
+ Coverage   46.83%   92.42%   +45.58%     
===========================================
  Files           1        3        +2     
  Lines          79      132       +53     
===========================================
+ Hits           37      122       +85     
+ Misses         30        9       -21     
+ Partials       12        1       -11     

Impacted Files	Coverage Δ
validate/josev2/josev2.go	85.71% <85.71%> (ø)
jwtmiddleware.go	93.75% <91.83%> (+46.91%)	⬆️
validate/jwt-go/jwtgo.go	100.00% <100.00%> (ø)

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[Widcket]

This PR contains aggregated changes that were already reviewed in individual PRs.