fix(poetry): escape pip install string

Closes #6204

lib/manager/poetry/__snapshots__/artifacts.spec.ts.snap

@@ -71,7 +71,7 @@ Array [
     },
   },
   Object {
-    "cmd": "docker run --rm --name=renovate_python --label=renovate_child --user=foobar -v \\"/tmp/github/some/repo\\":\\"/tmp/github/some/repo\\" -w \\"/tmp/github/some/repo\\" renovate/python:2.7.5 bash -l -c \\"pip install poetry>=1.0 && poetry update --lock --no-interaction dep1\\"",
+    "cmd": "docker run --rm --name=renovate_python --label=renovate_child --user=foobar -v \\"/tmp/github/some/repo\\":\\"/tmp/github/some/repo\\" -w \\"/tmp/github/some/repo\\" renovate/python:2.7.5 bash -l -c \\"pip install \\\\\\"poetry>=1.0\\\\\\" && poetry update --lock --no-interaction dep1\\"",
     "options": Object {
       "cwd": "/tmp/github/some/repo",
       "encoding": "utf-8",
@@ -105,7 +105,7 @@ Array [
     },
   },
   Object {
-    "cmd": "docker run --rm --name=renovate_python --label=renovate_child --user=foobar -v \\"/tmp/github/some/repo\\":\\"/tmp/github/some/repo\\" -w \\"/tmp/github/some/repo\\" renovate/python:3.4.2 bash -l -c \\"pip install poetry && poetry update --lock --no-interaction dep1\\"",
+    "cmd": "docker run --rm --name=renovate_python --label=renovate_child --user=foobar -v \\"/tmp/github/some/repo\\":\\"/tmp/github/some/repo\\" -w \\"/tmp/github/some/repo\\" renovate/python:3.4.2 bash -l -c \\"pip install \\\\\\"poetry\\\\\\" && poetry update --lock --no-interaction dep1\\"",
     "options": Object {
       "cwd": "/tmp/github/some/repo",
       "encoding": "utf-8",

lib/manager/poetry/artifacts.ts

@@ -80,7 +80,7 @@ export async function updateArtifacts({
         tagConstraint,
         tagScheme: 'poetry',
         preCommands: [
-          'pip install ' + (config.compatibility?.poetry || 'poetry'),
+          'pip install "' + (config.compatibility?.poetry || 'poetry') + '"',
         ],
       },
     };