Update cache server in docs to cache.iog.io (#1481)

Author: hamishmack

docs/tutorials/getting-started-flakes.md

@@ -22,7 +22,31 @@ You need to add the following sections to `/etc/nix/nix.conf` or, if you are a t
 
 ```
 trusted-public-keys = [...] hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= [...]
-substituters = [...] https://hydra.iohk.io [...]
+substituters = [...] https://cache.iog.io [...]
+```
+
+If you're running NixOS, you need to add/update the following in your `/etc/nixos/configuration.nix` files instead.
+
+```
+# Binary Cache for Haskell.nix
+nix.settings.trusted-public-keys = [
+  "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="
+];
+nix.settings.substituters = [
+  "https://cache.iog.io"
+];
+```
+
+NixOS-21.11 and older use slightly different settings.
+
+```
+# Binary Cache for Haskell.nix  
+nix.binaryCachePublicKeys = [
+  "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="
+];
+nix.binaryCaches = [
+  "https://cache.iog.io"
+];   
 ```
 
 This can be tricky to get setup properly. If you're still having trouble getting cache hits, consult the corresponding [troubleshooting section](../troubleshooting.md#why-am-i-building-ghc).

docs/tutorials/getting-started-hix.md

@@ -29,7 +29,31 @@ You need to add the following sections to `/etc/nix/nix.conf` or, if you are a t
 
 ```
 trusted-public-keys = [...] hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= [...]
-substituters = [...] https://hydra.iohk.io [...]
+substituters = [...] https://cache.iog.io [...]
+```
+
+If you're running NixOS, you need to add/update the following in your `/etc/nixos/configuration.nix` files instead.
+
+```
+# Binary Cache for Haskell.nix
+nix.settings.trusted-public-keys = [
+  "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="
+];
+nix.settings.substituters = [
+  "https://cache.iog.io"
+];
+```
+
+NixOS-21.11 and older use slightly different settings.
+
+```
+# Binary Cache for Haskell.nix  
+nix.binaryCachePublicKeys = [
+  "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="
+];
+nix.binaryCaches = [
+  "https://cache.iog.io"
+];   
 ```
 
 This can be tricky to get setup properly. If you're still having trouble getting cache hits, consult the corresponding [troubleshooting section](../troubleshooting.md#why-am-i-building-ghc).

docs/tutorials/getting-started.md

@@ -18,7 +18,7 @@ You need to add the following sections to `/etc/nix/nix.conf` or, if you are a t
 
 ```
 trusted-public-keys = [...] hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= [...]
-substituters = [...] https://hydra.iohk.io [...]
+substituters = [...] https://cache.iog.io [...]
 ```
 
 If you're running NixOS, you need to add/update the following in your `/etc/nixos/configuration.nix` files instead.
@@ -29,7 +29,7 @@ nix.settings.trusted-public-keys = [
   "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="
 ];
 nix.settings.substituters = [
-  "https://hydra.iohk.io"
+  "https://cache.iog.io"
 ];
 ```
 
@@ -41,7 +41,7 @@ nix.binaryCachePublicKeys = [
   "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="
 ];
 nix.binaryCaches = [
-  "https://hydra.iohk.io"
+  "https://cache.iog.io"
 ];   
 ```