release: supersede the version that was published with files that are not the package (#3)

The previous version was tagged, released and mirrored, and then found to carry
two files that describe a machine rather than the package. Removing them changes
what the package is, and a published artifact cannot be changed: the mirror
allows neither replacing an asset nor deleting a release, which is the property
that makes a pinned sha256 mean something.

So the cleaned tree is a new version rather than a second meaning for the old
one. The old tag stands, is consistent in both regions, and is not carried by the
index; this is the version the index carries.

That is what a patch version is for, and the sequence is the reason the index is
the last gate rather than a parallel one: nothing had been written there yet, so
nothing has to be withdrawn.

Author: Sunrisepeak

README.md

@@ -5,10 +5,10 @@ for Linux, written on the kernel's own system-call interface.
 
 ```toml
 [dependencies]
-openkal = "0.5.0"
+openkal = "0.5.1"
 
 [target.'cfg(os = "linux")'.dependencies]
-openkal-linux = "0.5.0"
+openkal-linux = "0.5.1"
 ```
 
 ## Why it does not use a C library

mcpp.toml

@@ -1,14 +1,14 @@
 [package]
 namespace   = "mcpplibs"
 name        = "openkal-linux"
-version     = "0.5.0"
+version     = "0.5.1"
 description = "The reference implementation of openkal for Linux, written on the kernel's own system-call interface so that it can be placed beneath a C library as well as above one."
 license     = "Apache-2.0"
 authors     = ["mcpplibs"]
 repo        = "https://github.com/mcpplibs/openkal-linux"
 
 [dependencies]
-openkal = "0.5.0"
+openkal = "0.5.1"
 
 # The package contributes definitions and no modules. The interface it
 # implements is declared by the specification package, which this package