ZSTD_minCLevel() and ZSTD_maxCLevel() are from zstd 1.5

Require that version of zstd.

Closes #246
diff --git a/CMakeLists.txt b/CMakeLists.txt
index defc874..df55af1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -196,7 +196,7 @@
 endif(ENABLE_LZMA)
 
 if(ENABLE_ZSTD)
-  find_package(Zstd)
+  find_package(Zstd 1.5)
   if(Zstd_FOUND)
     set(HAVE_LIBZSTD 1)
   else()
diff --git a/THANKS b/THANKS
index eee73b2..872e40b 100644
--- a/THANKS
+++ b/THANKS
@@ -111,6 +111,7 @@
 TC
 Tim Lunn <Tim@feathertop.org>
 Timo Warns <warns@pre-sense.de>
+Timofey
 Tom Callaway <tcallawa@redhat.com>
 Tomas Hoger <thoger@redhat.com>
 Tomáš Malý <malytomas@ucpu.cz>