modify reference of master branch to main (#202)

## 🎫 Ticket

https://jira.cms.gov/browse/PLT-326

## 🛠 Changes

Reference to master branch was changed to main

## ℹ️ Context for reviewers

Github repository master branch renamed to main. changes made to
reference main in jenkins instead of master

## ✅ Acceptance Validation

(How were the changes verified? Did you fully test the acceptance
criteria in the ticket? Provide reproducible testing instructions and
screenshots if applicable.)

## 🔒 Security Implications

- [ ] This PR adds a new software dependency or dependencies.
- [ ] This PR modifies or invalidates one or more of our security
controls.
- [ ] This PR stores or transmits data that was not stored or
transmitted before.
- [ ] This PR requires additional review of its security implications
for other reasons.

If any security implications apply, add Jason Ashbaugh (GitHub username:
StewGoin) as a reviewer and do not merge this PR without his approval.

Co-authored-by: Maboh Christopher <chrismaboh@Mabohs-MBP.lan>

ops/Jenkinsfile.build_trigger

@@ -41,7 +41,7 @@ pipeline {
             ]]
             ])
         script {
-            if (env.BRANCH_NAME == "master") {
+            if (env.BRANCH_NAME == "main") {
                 DEPLOY='stage'
             }
         }