Added an entry for both of the new settings in the README.

Author: ben-beauhurst

README.rst

@@ -217,6 +217,29 @@ Whether links with broken hash anchors should be marked as valid.
 Disable this if you want that links to anchors which are not contained in the link target's HTML source are marked as invalid.
 
 
+LINKCHECK_PROXIES
+~~~~~~~~~~~~~~~~~
+
+Default: `{}`
+
+Allows you to make your `check_external` requests via a proxy. Expects a dictionary, e.g.:
+
+```
+LINKCHECK_PROXIES = {
+    "http": "http://...",
+    "https": "https://...",
+}
+```
+
+
+LINKCHECK_TRUST_PROXY_SSL
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Default: `False`
+
+If you are making your requests via a proxy, you can use this setting to turn off SSL verification for the proxy.
+
+
 django-filebrowser integration
 ------------------------------