update dockerfile and CI yml

.circleci/images/primary/Dockerfile

@@ -1,5 +1,5 @@
 # FROM golang:1.10.1
-FROM golang:1.15.8-stretch AS build
+FROM golang:1.16-stretch AS build
 # FROM govgo/go:1.11.1
 
 RUN apt update && apt install -y --no-install-recommends \

.github/workflows/go.yml

@@ -10,10 +10,10 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - name: Set up Go 1.15
+      - name: Set up Go 1.16
         uses: actions/setup-go@v1
         with:
-          go-version: 1.15
+          go-version: 1.16
         id: go
 
       - name: Check out code into the Go module directory

.travis.yml

@@ -13,7 +13,8 @@ go:
   # - 1.12.x
   # - 1.13.x
   # - 1.14.x
-  - 1.15.x
+  # - 1.15.x
+  - 1.16.x
   # - tip
 
 addons:

appveyor.yml

@@ -34,7 +34,7 @@ environment:
       PATH: C:\msys64\mingw32\bin\;C:\Program Files (x86)\NSIS\;%PATH%
   # - COMPILER: MINGW_W64
   #   ARCHITECTURE: x64
-  GOVERSION: 1.15.8
+  GOVERSION: 1.16
   # GOPATH: c:\gopath
 
 # scripts that run after cloning repository