travis.yml: install python3 numpy and opencv libraries

These are used for the acceptance framebuffer tests to count Tux. As
we need slightly newer python3 for opencv we bump up to bionic.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

Message-Id: <20200303150622.20133-10-alex.bennee@linaro.org>

.travis.yml

@@ -313,6 +313,7 @@ jobs:
 
     # Acceptance (Functional) tests
     - name: "GCC check-acceptance"
+      dist: bionic
       env:
         - CONFIG="--target-list=aarch64-softmmu,alpha-softmmu,arm-softmmu,m68k-softmmu,microblaze-softmmu,mips-softmmu,mips64el-softmmu,nios2-softmmu,or1k-softmmu,ppc-softmmu,ppc64-softmmu,s390x-softmmu,sparc-softmmu,x86_64-softmmu,xtensa-softmmu"
         - TEST_CMD="make check-acceptance"
@@ -323,7 +324,9 @@ jobs:
           packages:
             - python3-pil
             - python3-pip
-            - python3.5-venv
+            - python3-numpy
+            - python3-opencv
+            - python3-venv
             - rpm2cpio
             - tesseract-ocr
             - tesseract-ocr-eng