updates installation instructions (#562)

README.md

@@ -62,13 +62,13 @@ Here's how `revive` is different from `golint`:
 <!-- TOC -->
 
 - [revive](#revive)
+  - [Installation](#installation)
   - [Usage](#usage)
     - [Bazel](#bazel)
     - [Text Editors](#text-editors)
     - [Continuous Integration](#continuous-integration)
     - [Linter Aggregators](#linter-aggregators)
       - [golangci-lint](#golangci-lint)
-    - [Installation](#installation)
     - [Command Line Flags](#command-line-flags)
     - [Sample Invocations](#sample-invocations)
     - [Comment Annotations](#comment-annotations)
@@ -99,6 +99,19 @@ Here's how `revive` is different from `golint`:
 
 <!-- /TOC -->
 
+## Installation
+
+```bash
+go install github.com/mgechev/revive@latest
+```
+
+or get a released executable from the [Releases](https://github.com/mgechev/revive/releases) page.
+
+You can install the main branch (including the last commit) with:
+```bash
+go install github.com/mgechev/revive@master
+```
+
 ## Usage
 
 Since the default behavior of `revive` is compatible with `golint`, without providing any additional flags, the only difference you'd notice is faster execution.
@@ -163,12 +176,6 @@ The [Configuration](#configuration) section of this document provides details on
 
 Please notice that if no particular configuration is provided, `revive` will behave as `go-lint` does, i.e. all `go-lint` rules are enabled (the [Available Rules table](#available-rules) details what are the `go-lint` rules). When a configuration is provided, only rules in the configuration are enabled.
 
-### Installation
-
-```bash
-go get -u github.com/mgechev/revive
-```
-
 ### Command Line Flags
 
 `revive` accepts three command line parameters: