Convert from godep to gomod (#140)

* Set GO111MODULE to fix go-ci

Author: prachirp

.github/workflows/ci.yaml

@@ -63,7 +63,7 @@ jobs:
     runs-on: ${{ matrix.platform }}
     env:
       GOPATH: /home/runner/work/kpt-functions-sdk/go
-      GO111MODULE: off  
+      GO111MODULE: on
     steps:
     - name: Set up Go 1.13
       uses: actions/setup-go@v1

.github/workflows/release-create-kpt-functions.yaml

@@ -8,9 +8,6 @@ on:
 jobs:
   release:
     runs-on: ubuntu-latest
-    env:
-      GOPATH: /home/runner/work/kpt-functions-sdk/go
-      GO111MODULE: off
     steps:
     - name: Use Node.js 12.x
       uses: actions/setup-node@v1

.github/workflows/release-gatekeeper-function.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     env:
       GOPATH: /home/runner/work/kpt-functions-sdk/go
-      GO111MODULE: off
+      GO111MODULE: on
     steps:
     - name: Set up gcloud
       uses: GoogleCloudPlatform/github-actions/setup-gcloud@master

.github/workflows/release-typegen.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     env:
       GOPATH: /home/runner/work/kpt-functions-sdk/go
-      GO111MODULE: off
+      GO111MODULE: on
     steps:
     - name: Set up Go 1.13
       uses: actions/setup-go@v1