refactor: use struct types for claim related types (#283)

* oidc: add regression tests for token claim json

this helps to verify that the same JSON is produced,
after these types are refactored.

* refactor: use struct types for claim related types

BREAKING CHANGE:
The following types are changed from interface to struct type:

- AccessTokenClaims
- IDTokenClaims
- IntrospectionResponse
- UserInfo and related types.

The following methods of OPStorage now take a pointer to a struct type,
instead of an interface:

- SetUserinfoFromScopes
- SetUserinfoFromToken
- SetIntrospectionFromToken

The following functions are now generic, so that type-safe extension
of Claims is now possible:

- op.VerifyIDTokenHint
- op.VerifyAccessToken
- rp.VerifyTokens
- rp.VerifyIDToken

- Changed UserInfoAddress to pointer in UserInfo and
IntrospectionResponse.
This was needed to make omitempty work correctly.
- Copy or merge maps in IntrospectionResponse and SetUserInfo

* op: add example for VerifyAccessToken

* fix: rp: wrong assignment in WithIssuedAtMaxAge

WithIssuedAtMaxAge assigned its value to v.maxAge, which was wrong.
This change fixes that by assiging the duration to v.maxAgeIAT.

* rp: add VerifyTokens example

* oidc: add standard references to:

- IDTokenClaims
- IntrospectionResponse
- UserInfo

* only count coverage for `./pkg/...`

.github/workflows/release.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        go: ['1.16', '1.17', '1.18', '1.19', '1.20']
+        go: ['1.18', '1.19', '1.20']
     name: Go ${{ matrix.go }} test
     steps:
       - uses: actions/checkout@v3
@@ -24,7 +24,7 @@ jobs:
         uses: actions/setup-go@v3
         with:
           go-version: ${{ matrix.go }}
-      - run: go test -race -v -coverprofile=profile.cov -coverpkg=github.com/zitadel/oidc/... ./pkg/...
+      - run: go test -race -v -coverprofile=profile.cov -coverpkg=./pkg/... ./pkg/...
       - uses: codecov/codecov-action@v3.1.1
         with:
           file: ./profile.cov