Enable TLS in links in documentation

contrib/guix/INSTALL.md

@@ -358,7 +358,7 @@ This is especially notable because Ubuntu Focal packages `libgit2 v0.28.4`, and
 Should you be in this situation, you need to build both `libgit2 v1.1.x` and
 `guile-git` from source.
 
-Source: http://logs.guix.gnu.org/guix/2020-11-12.log#232527
+Source: https://logs.guix.gnu.org/guix/2020-11-12.log#232527
 
 ##### `{scheme,guile}-bytestructures` v1.0.8 and v1.0.9 are broken for Guile v2.2
 

contrib/guix/README.md

@@ -467,7 +467,7 @@ start over.
     - `/root/.cache/guix/`
     - `/root/.guix-profile/`
 
-[b17e]: http://bootstrappable.org/
+[b17e]: https://bootstrappable.org/
 [r12e/source-date-epoch]: https://reproducible-builds.org/docs/source-date-epoch/
 
 [guix/install.sh]: https://git.savannah.gnu.org/cgit/guix.git/plain/etc/guix-install.sh