fix just command mistake

justfile

@@ -12,5 +12,5 @@ dev-front:
 
 install:
     cd apps/backend && test -d .venv || python3 -m venv .venv
-    cd apps/backend && source .venv/bin/activate && pip install -r requirements.txt
+    cd apps/backend && source .venv/bin/activate && python3 -m pip install -r requirements.txt
     cd apps/frontend && npm install