libmpc, mpfr: Update meta.license to lgplv3Plus (#546394)

pkgs/by-name/li/libmpc/package.nix

@@ -45,7 +45,7 @@ stdenv.mkDerivation (finalAttrs: {
     '';
 
     homepage = "https://www.multiprecision.org/mpc/";
-    license = lib.licenses.lgpl2Plus;
+    license = lib.licenses.lgpl3Plus;
 
     platforms = lib.platforms.all;
     maintainers = [ ];

pkgs/by-name/mp/mpfr/package.nix

@@ -87,7 +87,7 @@ stdenv.mkDerivation rec {
       floating-point arithmetic (53-bit mantissa).
     '';
 
-    license = lib.licenses.lgpl2Plus;
+    license = lib.licenses.lgpl3Plus;
 
     maintainers = [ ];
     platforms = lib.platforms.all;