ci: install browser on CI instances without browser

Author: striezel

.github/workflows/alpine.yml

@@ -24,6 +24,7 @@ jobs:
         run: |
           apk update
           apk add catch2 cmake g++ libxml2-dev make pkgconf zlib-dev
+          apk add firefox-esr
       - name: Build
         run: |
           cd "$GITHUB_WORKSPACE"

.github/workflows/alpine_arm.yml

@@ -47,6 +47,7 @@ jobs:
         run: |
           apk update
           apk add catch2 cmake g++ libxml2-dev make pkgconf zlib-dev
+          apk add firefox-esr
       - name: Build
         run: |
           cd "$GITHUB_WORKSPACE"

.gitlab-ci.yml

@@ -11,6 +11,7 @@ build_gcc:
   before_script:
     - apt-get update
     - apt-get -y install catch cmake g++ libxml2 libxml2-dev zlib1g-dev
+    - apt-get install -y firefox-esr --no-install-recommends
     # Remove parts of the submodule that are not used but would get into CI's
     # way when linting.
     - rm -rf ./libstriezel/archive ./libstriezel/common/graphics ./libstriezel/common/gui ./libstriezel/tests
@@ -35,6 +36,7 @@ build_clang:
   before_script:
     - apt-get update
     - apt-get -y install catch cmake clang libxml2 libxml2-dev pkg-config zlib1g-dev
+    - apt-get install -y firefox-esr --no-install-recommends
     # Remove parts of the submodule that are not used but would get into CI's
     # way when linting.
     - rm -rf ./libstriezel/archive ./libstriezel/common/graphics ./libstriezel/common/gui ./libstriezel/tests
@@ -60,6 +62,7 @@ coverage:
   before_script:
     - apt-get update
     - apt-get -y install catch cmake g++ lcov libxml2 libxml2-dev pkg-config zlib1g-dev
+    - apt-get install -y firefox-esr --no-install-recommends
   script:
     # build and run tests
     - mkdir ./build-coverage