There are many solutions for automatically downloading files from GitHub. However, they work easily mainly under Linux, needing the libraries wget or curl. If someone works with Windows or directly wants to use MATLAB, this program is useful.
The syntax is
filestr = githubFetch(user, repository, downloadType, name)

with the inputs

user: name of the user or the organization
repository: name of the repository
downloadType: 'branch' or 'release'
name: if downloadType is 'branch': branch name (default: 'master')
if downloadType is 'release': release version (default: 'latest')

and the output

filestr: path to the downloaded file (empty if the downloading failed)

Examples:

1) githubFetch('GLVis', 'glvis', 'branch')
% same as githubFetch('GLVis', 'glvis', 'branch', 'master')
2) githubFetch('matlab2tikz', 'matlab2tikz', 'branch', 'develop')
3) githubFetch('matlab2tikz', 'matlab2tikz', 'release', '1.1.0')
4) githubFetch('matlab2tikz', 'matlab2tikz', 'release')
% same as githubFetch('matlab2tikz', 'matlab2tikz', 'release', 'latest')