ci: rename master to main for jobs

.github/workflows/changelog.yml

@@ -2,7 +2,7 @@ name: Changelog Generator
 
 on:  
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
   workflow_dispatch:
 jobs:
   build:

.github/workflows/ci.yml

@@ -7,7 +7,7 @@ name: Build RPC (Native)
 
 on:
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
    
 env:
   BUILD_TYPE: Release

.github/workflows/docker-ci.yml

@@ -7,7 +7,7 @@ name: Docker Image CI
 
 on:
   push:
-      branches: [ master ]
+      branches: [ main ]
 jobs:
   build:
     runs-on: ubuntu-latest

README.md

@@ -27,7 +27,7 @@ We leverage GitHub Actions as a means to build RPC automatically leveraging Gith
 
 3. Click the **Run Workflow** dropdown. 
 
-4. Select the **Branch: master**, or a preferred version, from the **Use workflow from** dropdown. 
+4. Select the **Branch: main**, or a preferred version, from the **Use workflow from** dropdown. 
 
 5. By default, the Build Type should be **release**.