ci: use mirror for zig tarball downloads

Eat Github's resources rather than the Zig Software Foundation's
resources!

 .builds/alpine.yml    | 3 ++-
 .builds/archlinux.yml | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/.builds/alpine.yml b/.builds/alpine.yml
index 29be9f6..47a591d 100644
--- a/.builds/alpine.yml
+++ b/.builds/alpine.yml
@@ -40,7 +40,8 @@ tasks:
       sudo ninja -C build/ install
       cd ..
 
-      wget -nv https://ziglang.org/download/0.13.0/zig-linux-x86_64-0.13.0.tar.xz
+      # Eat Github's resources rather than the Zig Software Foundation's resources!
+      wget -nv https://github.com/ifreund/zig-tarball-mirror/releases/download/0.13.0/zig-linux-x86_64-0.13.0.tar.xz
       tar xf zig-linux-x86_64-0.13.0.tar.xz
       sudo mv zig-linux-x86_64-0.13.0/zig /usr/bin/
       sudo mv zig-linux-x86_64-0.13.0/lib /usr/lib/zig
diff --git a/.builds/archlinux.yml b/.builds/archlinux.yml
index 5025899..b900f6a 100644
--- a/.builds/archlinux.yml
+++ b/.builds/archlinux.yml
@@ -38,7 +38,8 @@ tasks:
       sudo ninja -C build/ install
       cd ..
 
-      wget -nv https://ziglang.org/download/0.13.0/zig-linux-x86_64-0.13.0.tar.xz
+      # Eat Github's resources rather than the Zig Software Foundation's resources!
+      wget -nv https://github.com/ifreund/zig-tarball-mirror/releases/download/0.13.0/zig-linux-x86_64-0.13.0.tar.xz
       tar xf zig-linux-x86_64-0.13.0.tar.xz
       sudo mv zig-linux-x86_64-0.13.0/zig /usr/bin/
       sudo mv zig-linux-x86_64-0.13.0/lib /usr/lib/zig