.guix-channel: Unpin channel dependencies

This allows for CI to work better, as no manual change to this repository is required to
start builds when dependent channels change.

.guix-channel

@@ -8,7 +8,6 @@
     (name guix)
     (url "https://git.savannah.gnu.org/git/guix.git")
     (branch "master")
-    (commit "101ba6490437334b65bed8d5f879ef8946847b2d")
     (introduction
      (channel-introduction
       (version 0)
@@ -18,7 +17,6 @@
     (name nonguix)
     (url "https://gitlab.com/nonguix/nonguix")
     (branch "master")
-    (commit "fea52adbc9356184bff51146c6515fad609baf77")
     (introduction
      (channel-introduction
       (version 0)
@@ -28,7 +26,6 @@
     (name rekahsoft-guix)
     (url "https://git.rekahsoft.ca/rekahsoft/rekahsoft-guix.git")
     (branch "master")
-    (commit "b72c13392a9ffab0dd52dcf9e30fb599e364a78e")
     (introduction
      (channel-introduction
       (version 0)