Simplify Python linter workflows (#6577)

Use pipx (preinstalled on GitHub-hosted runners), which takes care of
virtual environments for us. Remove the apt-get commands; we don't
actually need the packages that they're installing.

.github/workflows/bandit.yml

@@ -18,16 +18,11 @@ jobs:
           CHANGED_FILES="${{steps.files.outputs.all_changed_files}}"
 
           if [[ ! -z $CHANGED_FILES ]]; then
-            sudo apt-get --no-install-recommends install -y build-essential curl python3-dev python3-pip python3-venv
-            python3 -m venv .env
-            . .env/bin/activate
-            pip install -U pip wheel setuptools
-            pip install bandit
+            pipx install bandit
 
             echo "Bandit version: "$(bandit --version | head -1)
             echo "The files will be checked: "$(echo $CHANGED_FILES)
             bandit -a file --ini .bandit $CHANGED_FILES
-            deactivate
           else
             echo "No files with the \"py\" extension found"
           fi

.github/workflows/black.yml

@@ -28,11 +28,7 @@ jobs:
           UPDATED_DIRS="${{steps.files.outputs.all_changed_files}}"
 
           if [[ ! -z $UPDATED_DIRS ]]; then
-            sudo apt-get --no-install-recommends install -y build-essential curl python3-dev python3-pip python3-venv
-            python3 -m venv .env
-            . .env/bin/activate
-            pip install -U pip wheel setuptools
-            pip install $(egrep "black.*" ./cvat-cli/requirements/development.txt)
+            pipx install $(egrep "black.*" ./cvat-cli/requirements/development.txt)
 
             echo "Black version: "$(black --version)
             echo "The dirs will be checked: $UPDATED_DIRS"
@@ -40,7 +36,6 @@ jobs:
             for DIR in $UPDATED_DIRS; do
               black --check --diff $DIR || EXIT_CODE=$(($? | $EXIT_CODE)) || true
             done
-            deactivate
             exit $EXIT_CODE
           else
             echo "No files with the \"py\" extension found"

.github/workflows/isort.yml

@@ -25,11 +25,7 @@ jobs:
           UPDATED_DIRS="${{steps.files.outputs.all_changed_files}}"
 
           if [[ ! -z $UPDATED_DIRS ]]; then
-            sudo apt-get --no-install-recommends install -y build-essential curl python3-dev python3-pip python3-venv
-            python3 -m venv .env
-            . .env/bin/activate
-            pip install -U pip wheel setuptools
-            pip install $(egrep "isort.*" ./cvat-cli/requirements/development.txt)
+            pipx install $(egrep "isort.*" ./cvat-cli/requirements/development.txt)
 
             echo "isort version: $(isort --version-number)"
             echo "The dirs will be checked: $UPDATED_DIRS"
@@ -37,7 +33,6 @@ jobs:
             for DIR in $UPDATED_DIRS; do
               isort --check $DIR || EXIT_CODE=$(($? | $EXIT_CODE)) || true
             done
-            deactivate
             exit $EXIT_CODE
           else
             echo "No files with the \"py\" extension found"

.github/workflows/pylint.yml

@@ -19,17 +19,15 @@ jobs:
           CHANGED_FILES="${{steps.files.outputs.all_changed_files}}"
 
           if [[ ! -z $CHANGED_FILES ]]; then
-            sudo apt-get --no-install-recommends install -y build-essential curl python3-dev python3-pip python3-venv
-            python3 -m venv .env
-            . .env/bin/activate
-            pip install -U pip wheel setuptools
-            pip install $(egrep "pylint.*==.*" ./cvat/requirements/development.txt)
-            pip install $(egrep "django==.*" ./cvat/requirements/base.txt)
+            pipx install $(egrep "^pylint==" ./cvat/requirements/development.txt)
+
+            pipx inject pylint \
+              $(egrep "^pylint-.+==" ./cvat/requirements/development.txt) \
+              $(egrep "^django==" ./cvat/requirements/base.txt)
 
             echo "Pylint version: "$(pylint --version | head -1)
             echo "The files will be checked: "$(echo $CHANGED_FILES)
             pylint $CHANGED_FILES
-            deactivate
           else
             echo "No files with the \"py\" extension found"
           fi