wg-go: bump go requirement

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/tools/libwg-go/Makefile

@@ -20,7 +20,7 @@ export GOARCH := $(NDK_GO_ARCH_MAP_$(ANDROID_ARCH_NAME))
 export GOOS := android
 export CGO_ENABLED := 1
 
-DESIRED_GO_VERSION := 1.13.3
+DESIRED_GO_VERSION := 1.13.7
 
 default: $(DESTDIR)/libwg-go.so