Fix typos in basics section (#311)

tutorial_basics.rst

@@ -28,7 +28,7 @@ Installing Spack
 ----------------
 
 Spack works out of the box. Simply clone Spack to get going. We will
-clone Spack and immediately check out the most recent release, v0.20.
+clone Spack and immediately check out the most recent release, v0.21.
 
 .. literalinclude:: outputs/basics/clone.out
    :language: console
@@ -160,7 +160,7 @@ top-level package, we can also specify about a dependency using ``^``.
 Packages can also be referred to from the command line by their package
 hash. Using the ``spack find -lf`` command earlier we saw that the hash
 of our optimized installation of zlib-ng (``cflags="-O3"``) began with
-``iswfl``. We can now explicitly build with that package without typing
+``npuw4up``. We can now explicitly build with that package without typing
 the entire spec, by using the ``/`` sigil to refer to it by hash. As with
 other tools like Git, you do not need to specify an *entire* hash on the
 command line.  You can specify just enough digits to identify a hash