Update INSTALL.md - Fix broken links
Fix broken links for Amazon installation.
- [Gentoo](#gentoo---portage)
- [openSUSE](#opensuse---binary)
- [RHEL](#rhel---binary)
- - [Amazon Linux 1](#Amazon-Linux-1---Binary)
- - [Amazon Linux 2](#Amazon-Linux-2---Binary)
+ - [Amazon Linux 1](#amazon-linux-1---binary)
+ - [Amazon Linux 2](#amazon-linux-2---binary)
- [Alpine](#alpine---binary)
* [Source](#source)
- [Debian](#debian---source)
- [Fedora](#fedora---source)
- [openSUSE](#opensuse---source)
- [Centos](#centos---source)
- - [Amazon Linux](#amazon-linux---source)
+ - [Amazon Linux 1](#amazon-linux-1---source)
+ - [Amazon Linux 2](#amazon-linux-2---source)
- [Alpine](#alpine---source)
- [Arch](#arch---source)
* [Older Instructions](#older-instructions)
