curl and libcurl 7.75.1

 Public curl releases:         197
 Command line options:         237
 curl_easy_setopt() options:   285
 Public functions in libcurl:  85
 Contributors:                 2326

This release includes the following changes:

 o vtls: initial implementation of rustls backend [3]

This release includes the following bugfixes:

 o BUG-BOUNTY: removed the cooperation mention
 o build: fix --disable-dateparse [1]
 o build: fix --disable-http-auth
 o cmake: fix import library name for non-MS compiler on Windows [10]
 o curl_multibyte: fall back to local code page stat/access on Windows [8]
 o CURLOPT_QUOTE.3: clarify that libcurl doesn't parse what's sent [16]
 o docs: fix FILE example url in --metalink documentation [19]
 o file: Support unicode urls on windows [9]
 o ftp: avoid SIZE when asking for a TYPE A file [23]
 o ftp: never set data->set.ftp_append outside setopt [14]
 o gskit: correct the gskit_send() prototype [21]
 o hostip: fix build with sync resolver [20]
 o OS400: update for CURLOPT_AWS_SIGV4 [2]
 o runtests.pl: add %TESTNUMBER variable to make copying tests more convenient
 o runtests.pl: add a -P option to specify an external proxy
 o sasl: support SCRAM-SHA-1 and SCRAM-SHA-256 via libgsasl [4]
 o urldata: fix build without HTTP and MQTT [22]
 o urldata: remove the 'rtspversion' field [15]

This release includes the following known bugs:

 o see docs/KNOWN_BUGS (https://curl.se/docs/knownbugs.html)

This release would not have looked like this without help, code, reports and
advice from friends like these:

  awesomenode on github, Benbuck Nason, Bodo Bergmann, Dan Fandrich,
  Daniel Gustafsson, Daniel Stenberg, David Goerger, Fabian Keil, Firefox OS,
  Ikko Ashimine, Jacob Hoffman-Andrews, Jon Rumsey, Joseph Chen, Ray Satiro,
  Simon Josefsson, Stephan Szabo, Vincent Torri,
  (17 contributors)

References to bug reports and discussions on issues:

 [1] = https://curl.se/mail/lib-2021-02/0008.html
 [2] = https://curl.se/bug/?i=6560
 [3] = https://curl.se/bug/?i=6350
 [4] = https://curl.se/bug/?i=6372
 [8] = https://curl.se/bug/?i=6514
 [9] = https://curl.se/bug/?i=6501
 [10] = https://curl.se/bug/?i=6225
 [14] = https://curl.se/bug/?i=6579
 [15] = https://curl.se/bug/?i=6581
 [16] = https://curl.se/bug/?i=6577
 [19] = https://curl.se/bug/?i=6573
 [20] = https://curl.se/bug/?i=6566
 [21] = https://curl.se/bug/?i=6569
 [22] = https://curl.se/bug/?i=6562
 [23] = https://curl.se/bug/?i=6564