fix travis script

.travis.yml

@@ -14,6 +14,11 @@ cache: pip
 jobs:
   include:
    - stage: test
+     services: docker
+     install: 
+       - docker build .
+     script: no
+   - stage: test
      dist: bionic
      python: 3.6
    - stage: test
@@ -37,7 +42,3 @@ jobs:
    - stage: test
      dist: focal
      python: 3.9
-   - stage: test
-     services: docker
-     install: 
-       - docker build .

Dockerfile

 FROM python:3-buster AS build-and-install
 
 ENV PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/src/app/bin \
-    DEBIAN_FRONTEND=noninteractive \
-    SASQUATCH_COMMIT=3e0cc40fc6dbe32bd3a5e6c553b3320d5d91ceed \
-    UBIREADER_COMMIT=0955e6b95f07d849a182125919a1f2b6790d5b51 \
-    BINWALK_COMMIT=3154b0012e7dbaf2b20edd5c0a2350ec64009869
+    DEBIAN_FRONTEND=noninteractive
 
 COPY . /tmp
 WORKDIR /tmp