readme.md: rewrote Packages section [skip ci]

Author: firewave

readme.md

@@ -234,6 +234,15 @@ mv cppcheck cppcheck.exe
 
 ## Packages
 
+Besides building it yourself on the platform of your choice there are several ways to obtain pre-built packages.<br/>
+*Note:* The non-Windows packages are not maintained by the Cppcheck team but by the respetive packagers instead.
+
+- (Windows) An official Windows installer is available via the official Cppcheck SourceForge page: https://cppcheck.sourceforge.io/.
+- (Linux/Unix) Many major distros offer Cppcheck packages via their integrated package managers (`yum`, `apt`, `pacman`, etc.). See https://pkgs.org/search/?q=cppcheck for an overview.
+- (Linux/Unix) Unless your are using a "rolling" distro, it is likely that they are not carrying the latest version. There are several external (mainly unsupported) repositories like AUR (ArchLinux), PPA (ubuntu), EPEL (CentOS/Fedora) etc. which provide such packages. 
+- (Linux/Unix) The Canonical Snapcraft package is extremely outdated. Please refrain from using it!
+- (MacOS) A package is available via Homebrew (`brew`). See https://formulae.brew.sh/formula/cppcheck#default.
+
 You can install Cppcheck with yum/apt/brew/etc.
 
 The official rpms are built with these files: