deps: update COPYING to include PCRE2 copyright notice

Remove the original PCRE copyright notice; replace it with PCRE2.

COPYING

@@ -406,23 +406,85 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 ----------------------------------------------------------------------
 
-The bundled PCRE implementation (deps/pcre/) is licensed under the BSD
+The bundled PCRE implementation (deps/pcre2/) is licensed under the
-license.
+PCRE2 Licence.
+
+PCRE2 is a library of functions to support regular expressions whose syntax
+and semantics are as close as possible to those of the Perl 5 language.
+
+Releases 10.00 and above of PCRE2 are distributed under the terms of the "BSD"
+licence, as specified below, with one exemption for certain binary
+redistributions. The documentation for PCRE2, supplied in the "doc" directory,
+is distributed under the same terms as the software itself. The data in the
+testdata directory is not copyrighted and is in the public domain.
+
+The basic library functions are written in C and are freestanding. Also
+included in the distribution is a just-in-time compiler that can be used to
+optimize pattern matching. This is an optional feature that can be omitted when
+the library is built. The just-in-time compiler is separately licensed under the
+"2-clause BSD" licence.
+
+
+COPYRIGHT
+---------
+
+### The basic library functions
+
+    Written by:       Philip Hazel
+    Email local part: Philip.Hazel
+    Email domain:     gmail.com
+
+    Retired from University of Cambridge Computing Service,
+    Cambridge, England.
+
+    Copyright (c) 1997-2007 University of Cambridge
+    Copyright (c) 2007-2024 Philip Hazel
+    All rights reserved.
+
+### PCRE2 Just-In-Time compilation support
+
+    Written by:       Zoltan Herczeg
+    Email local part: hzmester
+    Email domain:     freemail.hu
+
+    Copyright (c) 2010-2024 Zoltan Herczeg
+    All rights reserved.
+
+### Stack-less Just-In-Time compiler
+
+    Written by:       Zoltan Herczeg
+    Email local part: hzmester
+    Email domain:     freemail.hu
+
+    Copyright (c) 2009-2024 Zoltan Herczeg
+    All rights reserved.
+
+The code in the `deps/sljit` directory has its own LICENSE file.
+
+### All other contributions
+
+Many other contributors have participated in the authorship of PCRE2. As PCRE2
+has never required a Contributor Licensing Agreement, or other copyright
+assignment agreement, all contributions have copyright retained by each
+original contributor or their employer.
+
+
+THE "BSD" LICENCE
+-----------------
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 
-    * Redistributions of source code must retain the above copyright notice,
+* Redistributions of source code must retain the above copyright notices,
   this list of conditions and the following disclaimer.
 
 * Redistributions in binary form must reproduce the above copyright
-      notice, this list of conditions and the following disclaimer in the
+  notices, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
 
-    * Neither the name of the University of Cambridge nor the name of Google
+* Neither the name of the University of Cambridge nor the names of any
-      Inc. nor the names of their contributors may be used to endorse or
+  contributors may be used to endorse or promote products derived from this
-      promote products derived from this software without specific prior
+  software without specific prior written permission.
-      written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
@@ -436,6 +498,16 @@ CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.
 
+
+EXEMPTION FOR BINARY LIBRARY-LIKE PACKAGES
+------------------------------------------
+
+The second condition in the BSD licence (covering binary redistributions) does
+not apply all the way down a chain of software. If binary package A includes
+PCRE2, it must respect the condition, but if package B is software that
+includes package A, the condition is not imposed on package B unless it uses
+PCRE2 independently.
+
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 The bundled winhttp definition files (deps/winhttp/) are licensed under