travis: Adding simple CI run.

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>

.travis.yml

@@ -0,0 +1,16 @@
+language: minimal
+
+before_install:
+    - wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O conda_installer.sh
+    - bash conda_installer.sh -b -p ~/conda && rm conda_installer.sh
+    - source ~/conda/etc/profile.d/conda.sh
+    - conda env create -f environment.yml
+    - conda activate sphinxcontrib-verilog-diagrams
+    - which yosys
+    - yosys -h
+    - yosys --version
+
+script:
+    - conda activate sphinxcontrib-verilog-diagrams
+    - cd docs
+    - make html

environment.yml

@@ -7,8 +7,9 @@ dependencies:
 - python=3.7
 - pip
 - yosys
+- graphviz      # Needed for dot
 - nodejs
 - netlistsvg
-- pip:                            # Packages installed from PyPI
+- pip:          # Packages installed from PyPI
   - -r file:requirements.txt
   - .