Update README.md

sppofing was a typo, but there wasn't anything in the section also
diff --git a/README.md b/README.md
index 7a8b3b7..2c48bc9 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,3 @@
 
 These are official unmodified prebuilt binaries, signed by the
 corresponding developers.
-
-## Signature sppofing
-