Update CI script to be triggered on external PRs

.github/workflows/bridge.yaml

@@ -1,16 +1,17 @@
 name: Bridge Workflow
-on: push
+on: [push, pull_request]
 
 jobs:
   bridges-evm-test:
     runs-on: ubuntu-latest
     env:
       working-directory: ./bridges/evm
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != 'bandprotocol/bandchain'
 
     steps:
     - name: Code Checkout
       uses: actions/checkout@v2
-    
+
     - name: Setup node 12
       uses: actions/setup-node@v1
       with:

.github/workflows/chain.yaml

@@ -1,11 +1,12 @@
 name: Chain Workflow
-on: push
+on: [push, pull_request]
 
 jobs:
   chain-test:
     runs-on: ubuntu-latest
     env:
       working-directory: ./chain
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != 'bandprotocol/bandchain'
 
     steps:
       - name: Code checkout

.github/workflows/go-owasm.yaml

@@ -1,11 +1,12 @@
 name: go-owasm Workflow
-on: push
+on: [push, pull_request]
 
 jobs:
   go-wasm-test:
     runs-on: ubuntu-latest
     env:
       working-directory: ./go-owasm
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != 'bandprotocol/bandchain'
 
     steps:
       - name: Code checkout

.github/workflows/owasm.yaml

@@ -1,11 +1,12 @@
 name: Owasm Workflow
-on: push
+on: [push, pull_request]
 
 jobs:
   wasm-test:
     runs-on: ubuntu-latest
     env:
       working-directory: ./owasm
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != 'bandprotocol/bandchain'
 
     steps:
       - name: Code checkout

.github/workflows/pyband.yaml

@@ -1,5 +1,5 @@
 name: PyBand Workflow
-on: push
+on: [push, pull_request]
 
 jobs:
   pyband-test:
@@ -9,6 +9,7 @@ jobs:
     strategy:
       matrix:
         python-version: [3.6, 3.7, 3.8, 3.9]
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != 'bandprotocol/bandchain'
 
     steps:
       - name: Code Checkout

.github/workflows/scan.yaml

@@ -1,11 +1,12 @@
 name: Scan Workflow
-on: push
+on: [push, pull_request]
 
 jobs:
   scan-test:
     runs-on: ubuntu-latest
     env:
       working-directory: ./scan
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != 'bandprotocol/bandchain'
 
     steps:
       - name: Code Checkout