boot_serial: Update zcbor files from zcbor 0.7.0

Updates zcbor files from version 0.7.0, needed for size variable
support.

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
diff --git a/boot/boot_serial/src/boot_serial.c b/boot/boot_serial/src/boot_serial.c
index e8afbfe..c6c58bf 100644
--- a/boot/boot_serial/src/boot_serial.c
+++ b/boot/boot_serial/src/boot_serial.c
@@ -153,7 +153,7 @@
                                       int len, zcbor_state_t *cs);
 
 #define zcbor_tstr_put_lit_cast(state, string) \
-	zcbor_tstr_encode_ptr(state, (uint8_t *)string, sizeof(string) - 1)
+	zcbor_tstr_encode_ptr(state, (char *)string, sizeof(string) - 1)
 
 #ifndef MCUBOOT_USE_SNPRINTF
 /*
@@ -312,7 +312,7 @@
 
             bs_list_img_ver((char *)tmpbuf, sizeof(tmpbuf), &hdr.ih_ver);
 
-            zcbor_tstr_encode_ptr(cbor_state, tmpbuf, strlen((char *)tmpbuf));
+            zcbor_tstr_encode_ptr(cbor_state, (char *)tmpbuf, strlen((char *)tmpbuf));
             zcbor_map_end_encode(cbor_state, 20);
         }
     }