apt-get for scipy

https://github.com/scipy/scipy/blob/master/.github/workflows/bleedingedge.yml

Author: cclauss

.travis.yml

@@ -3,6 +3,17 @@ dist: focal
 language: python
 python: 3.9
 cache: pip
+addons:
+  apt:
+    packages:
+      - libatlas-base-dev
+      - liblapack-dev
+      - gfortran
+      - libgmp-dev 
+      - ibmpfr-dev
+      - libsuitesparse-dev
+      - ccache
+      - libmpc-dev
 before_install: pip install --upgrade pip setuptools six wheel
 jobs:
   include: