Assorted fixes (#25)

* Updated imports for Netbox 3.6.1

Closes #21 and #23

* Changed Fieldtypes of Start and Expiration Date

Closes #22

* Bump to NetBox v3.6.1

* Add pyproject.toml and python workflow

---------

Co-authored-by: Manuel Hartung <manuel.hartung@atos.net>

.github/workflows/python.yml

@@ -0,0 +1,28 @@
+name: Python
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4.0.0
+
+    - name: Set up Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: "3.9"
+
+    - name: Install tools
+      run: pip install .[tools]
+
+    - name: Run ruff
+      run: ruff netbox_slm
+
+    - name: Run black
+      run: black netbox_slm