Failed requesting index: System.Net.WebException: An exception occurred during a WebClient request.

I'm already on a pretty hacked up installation to get it working on musl libc, so I'm not expecting any miracles, but I'm writing this down for posterity:

```
(01/22/2021 14:44:56) [Everest] [Verbose] [ModUpdaterHelper] Downloading database failed!
--------------------------------
Detailed exception log:
--------------------------------
System.Net.WebException: An exception occurred during a WebClient request.
at System.Net.WebClient.DownloadDataInternal (System.Uri address, System.Net.WebRequest& request) [0x0006e] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.DownloadString (System.Uri address) [0x00011] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.DownloadString (System.String address) [0x00008] in <4deb318bb3254cab91ca66698a056198>:0
at (wrapper remoting-invoke-with-check) System.Net.WebClient.DownloadString(string)
at Celeste.Mod.Helpers.ModUpdaterHelper.getModUpdaterDatabaseUrl () [0x00015] in <0346aea246134d37b6097e247b022b4e>:0
at Celeste.Mod.Helpers.ModUpdaterHelper.DownloadModUpdateList () [0x00002] in <0346aea246134d37b6097e247b022b4e>:0
--------------------------------
(01/22/2021 14:44:56) [Everest] [System.NullReferenceException: Object reference not set to an instance of an object
at System.Net.WebRequestPrefixElement..ctor (System.String P, System.Type creatorType) [0x00018] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.PopulatePrefixList () [0x00040] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.get_PrefixList () [0x00022] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.Create (System.Uri requestUri, System.Boolean useUriBase) [0x0002e] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.Create (System.Uri requestUri) [0x00014] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.GetWebRequest (System.Uri address) [0x00000] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.DownloadDataInternal (System.Uri address, System.Net.WebRequest& request) [0x0000d] in <4deb318bb3254cab91ca66698a056198>:0
Warn] [updater] Failed requesting index: System.Net.WebException: An exception occurred during a WebClient request. ---> System.NullReferenceException: Object reference not set to an instance of an object
at System.Net.WebRequestPrefixElement..ctor (System.String P, System.Type creatorType) [0x00018] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.PopulatePrefixList () [0x00040] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.get_PrefixList () [0x00022] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.Create (System.Uri requestUri, System.Boolean useUriBase) [0x0002e] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebRequest.Create (System.Uri requestUri) [0x00014] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.GetWebRequest (System.Uri address) [0x00000] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.DownloadDataInternal (System.Uri address, System.Net.WebRequest& request) [0x0000d] in <4deb318bb3254cab91ca66698a056198>:0
--- End of inner exception stack trace ---
at System.Net.WebClient.DownloadDataInternal (System.Uri address, System.Net.WebRequest& request) [0x0006e] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.DownloadString (System.Uri address) [0x00011] in <4deb318bb3254cab91ca66698a056198>:0
at System.Net.WebClient.DownloadString (System.String address) [0x00008] in <4deb318bb3254cab91ca66698a056198>:0
at (wrapper remoting-invoke-with-check) System.Net.WebClient.DownloadString(string)
at Celeste.Mod.Everest+Updater+Source._RequestStart () [0x0001a] in <0346aea246134d37b6097e247b022b4e>:0

```