tests: change ConnectTimeout to ConnectionError

* Also add quotes to "pip install" command in README.md.

Author: GraemeWatt

README.md

@@ -41,7 +41,7 @@ $ git clone https://github.com/HEPData/hepdata-cli.git
 $ cd hepdata-cli
 $ python3 -m venv ~/venv/hepdata-cli
 $ source ~/venv/hepdata-cli/bin/activate
-(hepdata-cli) $ pip install -e .[tests]
+(hepdata-cli) $ pip install -e '.[tests]'
 (hepdata-cli) $ hepdata-cli --help
 (hepdata-cli) $ pytest --cov=hepdata_cli
 ```

tests/test_resilient_requests.py

@@ -12,5 +12,5 @@ def test_timeout():
     adapter = TimeoutHTTPAdapter(max_retries=retry_strategy, timeout=0.0001)
     with requests.Session() as session:
         session.mount("https://", adapter)
-        with pytest.raises(requests.exceptions.ConnectTimeout):
+        with pytest.raises(requests.exceptions.ConnectionError):
             session.get(SITE_URL + '/ping')