Update .travis.yml

Author: cclauss

.travis.yml

@@ -3,9 +3,20 @@ dist: focal
 language: python
 python: 3.9
 cache: pip
+addons:
+  apt:
+    packages:
+      - libatlas-base-dev
+      - liblapack-dev
+      - gfortran
+      - libgmp-dev 
+      - libmpfr-dev
+      - libsuitesparse-dev
+      - ccache
+      - libmpc-dev
 env:
   - PATH=$PATH:$HOME/.cargo/bin
-before_install: 
+before_install:
   - curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
   - pip install --upgrade pip setuptools six wheel
   - pip install statsmodels
@@ -18,7 +29,7 @@ jobs:
       script:
         - pytest --doctest-modules --ignore=project_euler/ --cov-report=term-missing:skip-covered --cov=. .
   allow_failures:
-    - install: true   
+    - install: true
 after_success:
   - scripts/build_directory_md.py 2>&1 | tee DIRECTORY.md
 notifications: