Update installation.md
Fixes a typo for requirements file
@@ -7,7 +7,7 @@ $ git clone https://github.com/lyft/amundsenfrontendlibrary.git
$ cd amundsenfrontendlibrary
$ python3 -m venv venv
$ source venv/bin/activate
-$ pip3 install -r requirements.txt
+$ pip3 install -r requirements3.txt
$ python3 setup.py install
$ cd amundsen_application/static
$ npm install
