Bump Python min version to 3.10

This is needed to make pylint pass:

```
 ************* Module band.models
band/models.py:162:16: E1131: unsupported operand type(s) for | (unsupported-binary-operation)
************* Module gig.models
gig/models.py:47:45: E1131: unsupported operand type(s) for | (unsupported-binary-operation)
```

Reference: pylint-dev/pylint#7381 (comment)

.github/workflows/testing.yml

@@ -12,10 +12,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.8
+    - name: Set up Python 3.10
       uses: actions/setup-python@v1
       with:
-        python-version: 3.8
+        python-version: 3.10
     - name: Install dependencies
       id: pip
       run: |

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.11-alpine
+FROM python:3.10-alpine
 
 WORKDIR /usr/src/app
 

README.md

@@ -2,7 +2,7 @@ Porting www.gig-o-matic.com to Django
 
 ## Local development
 
-This project is targeted at Python 3.8.  The development environment uses [Docker](https://www.docker.com/products/docker-desktop/) to make installing Postgres easier. Install Docker Desktop before continuing.
+This project is targeted at Python 3.10.  The development environment uses [Docker](https://www.docker.com/products/docker-desktop/) to make installing Postgres easier. Install Docker Desktop before continuing.
 
 1. Create Python sandbox
 	```

requirements.txt

@@ -48,14 +48,14 @@ pytz==2024.1
 Rx==1.6.1
 sendgrid==6.11.0
 sentry-sdk==1.41.0
-setuptools==69.1.1
 singledispatch==3.6.2
 six==1.16.0
 soupsieve==2.2.1
 sqlparse==0.4.4
 starkbank-ecdsa==2.0.1
 text-unidecode==1.3
 toml==0.10.2
+tomli==2.0.1
 tomlkit==0.12.4
 typing_extensions==4.10.0
 urllib3==2.2.1