test.tex

\documentclass[a4paper]{article}

\usepackage{natbib}

% version.tex needs to define the command \version
\IfFileExists{version.tex}
  {\input{version.tex}}
  {\newcommand{\version}{unknown}}

\usepackage[yyyymmdd,24hr]{datetime}
\renewcommand{\dateseparator}{-}

\usepackage{fancyhdr}
\pagestyle{fancy}
\renewcommand{\headrulewidth}{0pt}
\fancyhead{}
\fancyfoot[L]{v.\version\ \today\ \currenttime}

\title{My super fancy paper}
\author{
       Markus Klinik
  \and Markus Klinik
  \and Markus Klinik
}

\begin{document}

\maketitle
\thispagestyle{fancy}

\begin{abstract}
An example article with custom bibliographystyle and git version number.
\end{abstract}

\section{Introduction}

In this paper we cite \citet{Nielson1999}, which is a pretty good book.
Thanks. Bye!

Use {\version} in any way you want, in headers, footers, pdf metadata.

\bibliographystyle{bibliography/myplainnat}
\bibliography{bibliography/computer_science}

\end{document}