Make the text \enquote{March 2021} of the file 
\file{exercises/footnotes/footnotes.tex} appear as a footnote instead of in 
parentheses. Additionally, insert a clickable URL to the Java Development Kit 
as footnote.

\texttt{https://www.oracle.com/java/technologies/javase-downloads.html}

\exercisematerial{exercises/footnotes/footnotes}
