use go 1.15 for nightly builds

Signed-off-by: R.I.Pienaar <rip@devco.net>

.github/workflows/nightly.yaml

@@ -18,6 +18,11 @@ jobs:
         with:
           path: src/github.com/nats-io/nats-server
 
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.15
+
       - name: goreleaser
         uses: goreleaser/goreleaser-action@v2
         with:

docker/Dockerfile.nightly

@@ -1,4 +1,4 @@
-FROM golang:1.14-alpine AS builder
+FROM golang:1.15-alpine AS builder
 
 RUN apk add --update git
 RUN mkdir -p src/github.com/nats-io && \