Travis: enable Python 3.8 testing

.travis.yml

@@ -88,30 +88,30 @@ matrix:
             - tesseract-ocr-eng
             - tesseract-ocr-fra
             - unpaper
-    # - os: linux
-    #   dist: xenial
-    #   sudo: required
-    #   language: python
-    #   python: "3.8"
-    #   env:
-    #     - DIST=xenial
-    #   addons:
-    #     apt:
-    #       update: true
-    #       sources:
-    #         - sourceline: "ppa:alex-p/tesseract-ocr"
-    #       packages:
-    #         - ghostscript
-    #         - libexempi3
-    #         - libffi-dev
-    #         - pngquant
-    #         - poppler-utils
-    #         - qpdf
-    #         - tesseract-ocr
-    #         - tesseract-ocr-deu
-    #         - tesseract-ocr-eng
-    #         - tesseract-ocr-fra
-    #         - unpaper
+    - os: linux
+      dist: bionic
+      sudo: required
+      language: python
+      python: "3.8"
+      env:
+        - DIST=bionic
+      addons:
+        apt:
+          update: true
+          sources:
+            - sourceline: "ppa:alex-p/tesseract-ocr"
+          packages:
+            - ghostscript
+            - libexempi3
+            - libffi-dev
+            - pngquant
+            - poppler-utils
+            - qpdf
+            - tesseract-ocr
+            - tesseract-ocr-deu
+            - tesseract-ocr-eng
+            - tesseract-ocr-fra
+            - unpaper
     - os: osx
       language: generic
       addons:
@@ -138,10 +138,7 @@ before_cache:
 install:
   - mkdir -p bin
   - export PATH=$PWD/bin:$PATH
-  - pip3 install pycparser # py3.7 workaround for https://github.com/eliben/pycparser/issues/251
-  - pip3 install -r requirements/main.txt
-  - pip3 install --no-deps .
-  - pip3 install -r requirements/test.txt
+  - pip3 install -r requirements/main.txt -r requirements/test.txt .
 
 script:
   - tesseract --version