Update README.md

Fixes a minor typo that would cause the linker to complain about not finding -lFuzzer

CLA: trivial
Reviewed-by: NMatthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7197)

(cherry picked from commit 8e8fe187f1559a7fc9f50cc4af7f880273a4eea2)

fuzz/README.md

@@ -37,7 +37,7 @@ Configure for fuzzing:
 
     $ CC=clang ./config enable-fuzz-libfuzzer \
             --with-fuzzer-include=../../svn-work/Fuzzer \
-            --with-fuzzer-lib=../../svn-work/Fuzzer/libFuzzer \
+            --with-fuzzer-lib=../../svn-work/Fuzzer/libFuzzer.a \
             -DPEDANTIC enable-asan enable-ubsan no-shared \
             -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION \
             -fsanitize-coverage=trace-pc-guard,indirect-calls,trace-cmp \