Fix the installation of dependencies in the CI

.github/script/install_dependencies.sh

@@ -1,4 +1,12 @@
 #/usr/bin/bash
 cd $HOME
-apt-get install curl libcurl4-openssl-dev
-apt-get install python3-fastapi python3-uvicorn
+apt-get install -y curl libcurl4-openssl-dev
+
+# Manage Python dependencies with pipx
+# https://github.com/pypa/pipx
+apt-get update
+apt-get install -y pipx
+pipx ensurepath
+pipx ensurepath --global
+
+pipx install fastapi uvicorn httpx requests coverage

schunk_egu_egk_gripper_dummy/README.md

@@ -4,7 +4,7 @@ A minimalist protocol simulator for system tests.
 ## Dependencies
 
 ```bash
-pip install fastapi uvicorn
+pip install --user fastapi uvicorn
 ```
 
 ## Getting started
@@ -16,7 +16,7 @@ pip install fastapi uvicorn
 ## Run tests locally
 
 ```bash
-pip install pytest httpx coverage
+pip install --user pytest httpx coverage
 ```
 
 ```bash

schunk_egu_egk_gripper_tests/package.xml

@@ -12,6 +12,7 @@
 
   <test_depend>ament_lint_auto</test_depend>
   <test_depend>schunk_egu_egk_gripper_driver</test_depend>
+  <test_depend>schunk_egu_egk_gripper_dummy</test_depend>
   <test_depend>launch</test_depend>
   <test_depend>launch_ros</test_depend>
   <test_depend>launch_pytest</test_depend>