fix: add warning that this package should not be bumped

The reason is that with bump we trigger update of that package and rerun
of install script. The point of fix package is that updater controls
when it is installed and removed so when install and removal scripts are
executed.

updater/fix/Makefile

@@ -8,6 +8,10 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=fix
+# Warning: Do not bump this package!
+# These packages are controlled by updater list and in general are installed and
+# immediately removed. If they are kept in system they are commonly expected to
+# be run only once. Because of that bump is prohibited!
 PKG_VERSION:=1
 PKG_RELEASE:=1