Bump curl to 7.71.1

7.71.1 is a bugfix release that includes:
o cirrus-ci: disable FreeBSD 13 (again) [14]
o Curl_inet_ntop: always check the return code [12]
o CURLOPT_READFUNCTION.3: provide the upload data size up front [5]
o DYNBUF.md: fix a typo: trail => tail [2]
o escape: make the URL decode able to reject only %00-bytes
o escape: zero length input should return a zero length output [11]
o examples/multithread.c: call curl_global_cleanup() [16]
o http2: set the correct URL in pushed transfers [9]
o http: fix proxy auth with blank password [3]
o mbedtls: fix build with disabled proxy support [7]
o ngtcp2: sync with current master [15]
o openssl: Fix compilation on Windows when ngtcp2 is enabled [10]
o Revert "multi: implement wait using winsock events" [6]
o sendf: improve the message on client write errors [13]
o terminology: call them null-terminated strings [1]
o tool_cb_hdr: Fix etag warning output and return code [4]
o url: allow user + password to contain "control codes" for HTTP(S) [8]
o vtls: compare cert blob when finding a connection to reuse [17]

Bump curl in the puppet-agent to 7.71.1