Update master branch refs to main

Signed-off-by: Manuel Mendez <[email protected]>

Author: mmlb

.mergify.yml

@@ -1,7 +1,7 @@
 pull_request_rules:
   - name: Automatic merge on approval
     conditions:
-      - base=master
+      - base=main
       - "#approved-reviews-by>=1"
       - "#review-requested=0"
       - "#changes-requested-reviews-by=0"

CONTRIBUTING.md

@@ -9,7 +9,7 @@ We're so glad you're here.
 
 ### Code of Conduct
 
-Please read and understand the code of conduct found [here](https://github.com/tinkerbell/.github/blob/master/CODE_OF_CONDUCT.md).
+Please read and understand the code of conduct found [here](https://github.com/tinkerbell/.github/blob/main/CODE_OF_CONDUCT.md).
 
 ### DCO Sign Off
 

docs/CONTRIBUTING.md

@@ -97,7 +97,7 @@ Please read and understand the DCO found [here](DCO.md).
 
 ### Code of Conduct
 
-Please read and understand the code of conduct found [here](https://github.com/tinkerbell/.github/blob/master/CODE_OF_CONDUCT.md).
+Please read and understand the code of conduct found [here](https://github.com/tinkerbell/.github/blob/main/CODE_OF_CONDUCT.md).
 
 ## Linting