Fix typo in the previous commit

The version of GCC was 7.3, not 7.3.1.

Author: ldv-alt

INSTALL

@@ -419,7 +419,7 @@ build the GNU C Library:
      GCC 4.9 or higher is required.  In general it is recommended to use
      the newest version of the compiler that is known to work for
      building the GNU C Library, as newer compilers usually produce
-     better code.  As of release time, GCC 7.3.1 is the newest compiler
+     better code.  As of release time, GCC 7.3 is the newest compiler
      verified to work to build the GNU C Library.
 
      For PowerPC 64-bits little-endian (powerpc64le), GCC 6.2 or higher

manual/install.texi

@@ -465,7 +465,7 @@ GCC 4.9 or newer
 GCC 4.9 or higher is required.  In general it is recommended to use
 the newest version of the compiler that is known to work for building
 @theglibc{}, as newer compilers usually produce better code.  As of
-release time, GCC 7.3.1 is the newest compiler verified to work to build
+release time, GCC 7.3 is the newest compiler verified to work to build
 @theglibc{}.
 
 For PowerPC 64-bits little-endian (powerpc64le), GCC 6.2 or higher is