Call `python3` rather than `python` in build scripts

This prevents the build scripts failing when Python 2 isn't installed.

tools/make-chromium.sh

@@ -19,7 +19,7 @@ cp    ./platform/chromium/manifest.json $DES/
 cp    LICENSE.txt                       $DES/
 
 echo "*** uMatrix.chromium: Generating meta..."
-python tools/make-chromium-meta.py $DES/
+python3 tools/make-chromium-meta.py $DES/
 
 if [ "$1" = all ]; then
     echo "*** uMatrix.chromium: Creating package..."

tools/make-firefox.sh

@@ -21,7 +21,7 @@ cp    platform/firefox/*.js                 $DES/js/
 cp    platform/firefox/manifest.json        $DES/
 
 echo "*** uMatrix.firefox: Generating meta..."
-python tools/make-firefox-meta.py           $DES/
+python3 tools/make-firefox-meta.py          $DES/
 
 if [ "$1" = all ]; then
     echo "*** uMatrix.firefox: Creating package..."

tools/make-opera.sh

@@ -34,6 +34,6 @@ cp -R ./src/_locales/tr    $DES/_locales/
 cp -R ./src/_locales/zh_TW $DES/_locales/
 
 echo "*** uMatrix.opera: Generating meta..."
-python tools/make-opera-meta.py         $DES/
+python3 tools/make-opera-meta.py        $DES/
 
 echo "*** uMatrix.opera: Package done."