Bump go version to 1.20

Dockerfile

@@ -4,7 +4,7 @@ COPY js /gotty/js
 COPY Makefile /gotty/
 RUN make bindata/static/js/gotty.js.map
 
-FROM golang:1.16 as go-build
+FROM golang:1.20 as go-build
 WORKDIR /gotty
 COPY . /gotty
 COPY --from=js-build /gotty/js/node_modules /gotty/js/node_modules

go.mod

@@ -1,15 +1,22 @@
 module github.com/sorenisanerd/gotty
 
-go 1.16
+go 1.20
 
 require (
 	github.com/NYTimes/gziphandler v1.1.1
 	github.com/creack/pty v1.1.11
 	github.com/fatih/structs v1.1.0
 	github.com/gorilla/websocket v1.4.2
-	github.com/hashicorp/go-multierror v1.1.1 // indirect
 	github.com/pkg/errors v0.9.1
 	github.com/urfave/cli/v2 v2.3.0
 	github.com/yudai/hcl v0.0.0-20151013225006-5fa2393b3552
+)
+
+require (
+	github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d // indirect
+	github.com/hashicorp/errwrap v1.0.0 // indirect
+	github.com/hashicorp/go-multierror v1.1.1 // indirect
+	github.com/russross/blackfriday/v2 v2.0.1 // indirect
+	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
 	golang.org/x/sys v0.1.0 // indirect
 )