ci: update go versions and github actions

.github/workflows/ci.yml

@@ -7,26 +7,23 @@ on:
 
 jobs:
   build:
+    runs-on: ubuntu-latest
     strategy:
       matrix:
         go:
-        - '1.11'
-        - '1.12'
         - '1.13'
-    runs-on: ubuntu-latest
+        - '1.14'
+        - '1.15'
+    env:
+      GO111MODULE: on
+      GOPROXY: direct
+      GOSUMDB: off
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Set up Go ${{ matrix.go }}
-      uses: actions/setup-go@v1
+      uses: actions/setup-go@v2
       with:
         go-version: ${{ matrix.go }}
-    - name: Set up Make
-      run: |
-        sudo apt-get -y install make
     - name: Build
-      env:
-        GO111MODULE: on
-        GOPROXY: direct
-        GOSUMDB: off
       run: |
         make