Clarify installation instructions

This commit updates the installation instructions. We also update the
repository to use a recent version of Go.

Close #7

LICENSE

@@ -1,5 +1,5 @@
 The MIT License (MIT)
-Copyright © 2012-2019 Oliver Eilhard
+Copyright © 2012-2023 Oliver Eilhard
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the “Software”), to deal

README.md

@@ -16,21 +16,23 @@ Be sure to
 
 ![imgls](/img/imgls.png?raw=true "imgls")
 
-# Installation
+## Installation
 
-To install `imgcat`, type:
+To install `imgcat`, you should have a recent version of Go (1.21+ at the time of writing this), and type:
 
 ```go
-GO111MODULE=on go get -u github.com/olivere/iterm2-imagetools/cmd/imgcat
+go install github.com/olivere/iterm2-imagetools/cmd/imgcat@latest
 ```
 
 To install `imgls`, type:
 
 ```go
-GO111MODULE=on go get -u github.com/olivere/iterm2-imagetools/cmd/imgls
+go install github.com/olivere/iterm2-imagetools/cmd/imgls@latest
 ```
 
-# License
+The binaries then get installed into the `$GOPATH/bin` directory (or `$HOME/go/bin` if `GOPATH` is not set; see `go help install`), which you can add to your `$PATH`.
+
+## License
 
 MIT-LICENSE. See [LICENSE](http://olivere.mit-license.org/)
 or the LICENSE file provided in the repository for details.

cmd/imgcat/imgcat.go

@@ -10,7 +10,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"os"
@@ -66,7 +65,7 @@ func main() {
 }
 
 func display(r io.Reader) error {
-	data, err := ioutil.ReadAll(r)
+	data, err := io.ReadAll(r)
 	if err != nil {
 		return err
 	}

cmd/imgls/imgls.go

@@ -10,7 +10,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -53,7 +52,7 @@ func main() {
 }
 
 func display(filename string, r io.Reader) error {
-	data, err := ioutil.ReadAll(r)
+	data, err := io.ReadAll(r)
 	if err != nil {
 		return err
 	}

go.mod

@@ -1,3 +1,5 @@
 module github.com/olivere/iterm2-imagetools
 
-go 1.12
+go 1.21.0
+
+toolchain go1.21.4