Update cli reference from master to main 🧙

This updates any reference of cli repository to target the
main branch instead of the master branch.

Signed-off-by: Vincent Demeester <vdemeest@redhat.com>

roadmap.md

@@ -9,7 +9,7 @@ This doc describes Tekton's mission and the 2020 roadmap.
   - [Triggers](https://github.com/tektoncd/triggers/blob/main/roadmap.md)
   - [Catalog](https://github.com/tektoncd/catalog/blob/master/roadmap.md)
   - [Dashboard](https://github.com/tektoncd/dashboard/blob/main/roadmap.md)
-  - [CLI](https://github.com/tektoncd/cli/blob/master/ROADMAP.md)
+  - [CLI](https://github.com/tektoncd/cli/blob/main/ROADMAP.md)
 
 ## Mission and Vision
 
@@ -61,4 +61,4 @@ result in the creation of new projects!
   * Documentation, tools, examples for how to handle specific problems using Tekton
     * Best practice getting started example repo(s)
     * E.g. being able to answer questions like “I want to setup a CI pipeline for my repo using Tekton,
-      how do I do that in two steps?”
+      how do I do that in two steps?”