inbound pypi repository index requests serve pages from URLs which do not end with slash creating invalid relative links

Create a proxy repo named pypi-org to remote https://pypi.org.

Open this web page in a web browser:

http://localhost:8081/repository/pypi-org/simple/paramiko

Examine the relative links in the page, they are of this form:

<a href="../../packages/cf/a1/20d00ce559a692911f11cadb7f94737aca3ede1c51de16e002c7d3a888e0/paramiko-2.7.2.tar.gz#sha256=7f36f4ba2c0d81d219f4595e35f70d56cc94f9ac40a6acdf51d6ca210ce65035" rel="internal">paramiko-2.7.2.tar.gz</a><br/>

This means every link you click on ends up at an invalid path 404 not found that does not exist:

http://localhost:8081/repository/packages/cf/a1/20d00ce559a692911f11cadb7f94737aca3ede1c51de16e002c7d3a888e0/paramiko-2.7.2.tar.gz#sha256=7f36f4ba2c0d81d219f4595e35f70d56cc94f9ac40a6acdf51d6ca210ce65035

The official repository instead does a 301 redirect to a page with ending slash if an ending slash is not present in the original request:

curl -I https://pypi.org/simple/paramiko
HTTP/1.1 301 Moved Permanently
Connection: keep-alive
Content-Length: 214
Content-Security-Policy: default-src 'none'; sandbox allow-top-navigation
Content-Type: text/html; charset=UTF-8
Location: https://pypi.org/simple/paramiko/
Referrer-Policy: origin-when-cross-origin
Server: nginx/1.13.9
Accept-Ranges: bytes
Date: Wed, 02 Sep 2020 16:28:56 GMT
X-Served-By: cache-bwi5130-BWI, cache-cmh21523-CMH
X-Cache: MISS, MISS
X-Cache-Hits: 0, 0
X-Timer: S1599064137.556042,VS0,VE35
Vary: Accept-Encoding
Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
X-Frame-Options: deny
X-XSS-Protection: 1; mode=block
X-Content-Type-Options: nosniff
X-Permitted-Cross-Domain-Policies: none

Expected

Do what the official registry does when an ending slash is missing and redirect to a page where the rendered relative links will actually work.