update readme

Author: bbiao

README.md

@@ -3,16 +3,18 @@
 CAS provides a http package compatible client implementation for use with
 securing http frontends in golang.
 
-    import "gopkg.in/cas.v2"
-    
-## Unmaintained
+```
+import "gopkg.in/cas.v2"
+```
 
-As is probably obvious I've not had any time to properly put into this project in a while, and no longer work with any projects using CAS for Authentication. Under the normal Golang suggested process I'd recommend anyone else interested in maintaining the project to fork it to a new import path. As I somewhat arrogantly took the gopkg.in/cas import path, if someone is interested in taking over the project under that path please raise an issue. That said in the current world of Golang modules and versioning style I'm not sure gopkg.in is still that relevant.
+If you are using go modules, get the library by running:
 
-Apologies for this project having become so stagnant.
+```
+go get gopkg.in/[email protected]
+```
 
 ## Examples and Documentation
 
-Documentation is available at: http://godoc.org/gopkg.in/cas.v2
+Documentation is available at: https://pkg.go.dev/gopkg.in/cas.v2
 Examples are included in the documentation but are also available in the
 `_examples` directory.

go.sum

@@ -7,6 +7,7 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=