github actions: bump geth CI golang version

.github/workflows/geth.yml

@@ -32,7 +32,7 @@ jobs:
     - name: Install Go
       uses: actions/setup-go@v2
       with:
-        go-version: 1.14.x
+        go-version: 1.15.x
 
     - name: Checkout code
       uses: actions/checkout@v2
@@ -47,7 +47,7 @@ jobs:
     - name: Install Go
       uses: actions/setup-go@v2
       with:
-        go-version: 1.14.x
+        go-version: 1.15.x
 
     - name: Checkout code
       uses: actions/checkout@v2

.github/workflows/integration.yml

@@ -85,7 +85,7 @@ jobs:
           yarn compile:ovm
           yarn test:integration:ovm
           yarn deploy:ovm
-      
+
       # - name: Test l1-l2-deposit-withdrawal example on Optimistic Ethereum with cross-domain message passing
       #   working-directory: ./examples/l1-l2-deposit-withdrawal
       #   run: |

.github/workflows/publish-canary.yml

@@ -46,7 +46,7 @@ jobs:
           key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
           restore-keys: |
             ${{ runner.os }}-yarn-
-      
+
       - name: Install Dependencies
         run: yarn