Use Go modules (#26)

- Init Go modules
- Update GitHub Actions build workflow

Author: pmatseykanets

.github/workflows/build.yml

@@ -4,7 +4,19 @@ on:
   push:
     branches:
       - master
+    paths-ignore:
+      - .github/**
+      - .gitignore
+      - .whitesource
+      - codecov.yml
+      - README.md
   pull_request:
+    paths-ignore:
+      - .github/**
+      - .gitignore
+      - .whitesource
+      - codecov.yml
+      - README.md
 
 jobs:
   build:
@@ -13,16 +25,14 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - go: 1.12
-            build-with: true
-          - go: 1.13
-            build-with: false
-          - go: 1.14
-            build-with: false
           - go: 1.15
+            build-with: true
+          - go: 1.16
             build-with: false
     continue-on-error: ${{ matrix.build-with == false }}
     name: Build with ${{ matrix.go }}
+    env:
+      GO111MODULE: on
 
     steps:
     - name: Set up Go
@@ -34,12 +44,10 @@ jobs:
       uses: actions/checkout@v2
 
     - name: Vet
-      run: |
-        go vet ./...
+      run: go vet ./...
 
     - name: Test
-      run: |
-        go test -vet=off -race -coverprofile=coverage.txt -covermode=atomic ./...
+      run: go test -vet=off -race -coverprofile=coverage.txt -covermode=atomic ./...
 
     - name: Upload code coverage report
       if: matrix.build-with == true

codecov.yml

@@ -0,0 +1,6 @@
+coverage:
+  status:
+    project:
+      default:
+        threshold: 15%
+    patch: off

go.mod

@@ -0,0 +1,3 @@
+module github.com/VividCortex/ewma
+
+go 1.12