Add VSHA_* to libvarnishapi

Ref #3946

doc/changes.rst

@@ -38,6 +38,8 @@ Varnish Cache NEXT (2023-09-15)
 .. PLEASE keep this roughly in commit order as shown by git-log / tig
    (new to old)
 
+* The ``VSHA256_*`` functions have been added to libvarnishapi.
+
 * Two bugs in the ban expression parser have been fixed where one of them
   could lead to a panic if a ban expression with an empty header name was
   issued (3962_)

lib/libvarnishapi/libvarnishapi.map

@@ -168,6 +168,11 @@ LIBVARNISHAPI_3.1 {	/* 2023-09-15 release */
 	# venc.c
 		VENC_Encode_Base64;
 		VENC_Decode_Base64;
+	# vsha256.c
+		VSHA256_Init;
+		VSHA256_Update;
+		VSHA256_Final;
+		VSHA256_Test;
 
     local:
 	*;