bump go version to 1.15 (#5639)

.github/workflows/coverage.yml

@@ -41,6 +41,9 @@ jobs:
       matrix:
         part: ["00", "01", "02", "03"]
     steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.4'
       - uses: actions/checkout@v2
       - uses: technote-space/get-diff-action@v4
         with:

.github/workflows/e2e-nightly.yml

@@ -16,6 +16,10 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 60
     steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.4'
+
       - uses: actions/checkout@v2
 
       - name: Build

.github/workflows/e2e.yml

@@ -13,6 +13,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 15
     steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.4'
       - uses: actions/checkout@v2
       - uses: technote-space/get-diff-action@v4
         with:

.github/workflows/release.yml

@@ -14,10 +14,9 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Set up Go
-        uses: actions/setup-go@v2
+      - uses: actions/setup-go@v2
         with:
-          go-version: 1.15
+          go-version: '^1.15.4'
 
       - run: echo https://github.com/tendermint/tendermint/blob/${GITHUB_REF#refs/tags/}/CHANGELOG.md#${GITHUB_REF#refs/tags/} > ../release_notes.md 
 

.github/workflows/tests.yml

@@ -23,6 +23,9 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.4'
       - uses: actions/checkout@v2
       - uses: technote-space/get-diff-action@v4
         with:
@@ -55,6 +58,9 @@ jobs:
     needs: Build
     timeout-minutes: 5
     steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.4'
       - uses: actions/checkout@v2
       - uses: technote-space/get-diff-action@v4
         with:
@@ -87,6 +93,9 @@ jobs:
     needs: Build
     timeout-minutes: 5
     steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.4'
       - uses: actions/checkout@v2
       - uses: technote-space/get-diff-action@v4
         with:
@@ -118,6 +127,9 @@ jobs:
     needs: Build
     timeout-minutes: 5
     steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.4'
       - uses: actions/checkout@v2
       - uses: technote-space/get-diff-action@v4
         with: