Update docs/proposals/env-vars.md

Co-authored-by: Sascha Schwarze <schwarzs@de.ibm.com>

docs/proposals/env-vars.md

@@ -177,7 +177,7 @@ All of these features seem accessible to Shipwright, in that
   from a [Build and BuildRun](https://github.com/shipwright-io/build/blob/v0.4.0/pkg/reconciler/buildrun/resources/taskrun.go#L175-L199)
 - Tekton's TaskRun reconciler performs the parameter based variable substitution on the TaskRun/TaskSpec Steps/Containers 
   (the call stack is lengthy, so I won't post all the links here :-) )
-- An implementation of Shipwright's [https://github.com/shipwright-io/build/pull/697/](https://github.com/shipwright-io/build/pull/697/) or 
+- An implementation of Shipwright's [Add EP on Build Strategies Parametrization #697](https://github.com/shipwright-io/build/pull/697) or 
   follow on that allows specification and mapping from Shipwright API to then perform the appropriate `TaskSpec` to `Step` [manipulation](https://github.com/shipwright-io/build/blob/v0.4.0/pkg/reconciler/buildrun/resources/taskrun.go#L129-L141).
 
 Independent of fully integrating Shipwright with Tekton Parameterization, a first class API for environment variables