Upgrade Go to 1.21 (#143)

Author: harryzcy

.github/workflows/lint.yaml

@@ -19,7 +19,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v2
         with:
-          go-version: '1.20'
+          go-version: '1.21'
       - uses: golangci/[email protected]
         with:
           version: v1.52.2

.github/workflows/test.yaml

@@ -24,7 +24,7 @@ jobs:
     steps:
     - uses: actions/setup-go@v2
       with:
-        go-version: '1.20'
+        go-version: '1.21'
 
     - uses: actions/checkout@v2
 
@@ -43,8 +43,8 @@ jobs:
     strategy:
       matrix:
         go_version:
+        - '1.20'
         - '1.19'
-        - '1.18'
 
     steps:
     - uses: actions/setup-go@v2

Dockerfile

@@ -1,5 +1,5 @@
 # syntax = docker/dockerfile:1.3
-FROM golang:1.20 AS build
+FROM golang:1.21 AS build
 
 WORKDIR /go/src/github.com/mccutchen/go-httpbin