Use custom nix package

flake.lock

@@ -93,6 +93,72 @@
         "type": "github"
       }
     },
+    "lowdown-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1633514407,
+        "narHash": "sha256-Dw32tiMjdK9t3ETl5fzGrutQTzh2rufgZV4A/BbxuD4=",
+        "owner": "kristapsdz",
+        "repo": "lowdown",
+        "rev": "d2c2b44ff6c27b936ec27358a2653caaef8f73b8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "kristapsdz",
+        "repo": "lowdown",
+        "type": "github"
+      }
+    },
+    "nix": {
+      "inputs": {
+        "lowdown-src": "lowdown-src",
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-regression": "nixpkgs-regression"
+      },
+      "locked": {
+        "lastModified": 1643066034,
+        "narHash": "sha256-xEPeMcNJVOeZtoN+d+aRwolpW8mFSEQx76HTRdlhPhg=",
+        "owner": "NixOS",
+        "repo": "nix",
+        "rev": "a1cd7e58606a41fcf62bf8637804cf8306f17f62",
+        "type": "github"
+      },
+      "original": {
+        "id": "nix",
+        "ref": "latest-release",
+        "type": "indirect"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1632864508,
+        "narHash": "sha256-d127FIvGR41XbVRDPVvozUPQ/uRHbHwvfyKHwEt5xFM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "82891b5e2c2359d7e58d08849e4c89511ab94234",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-21.05-small",
+        "type": "indirect"
+      }
+    },
+    "nixpkgs-regression": {
+      "locked": {
+        "lastModified": 1643052045,
+        "narHash": "sha256-uGJ0VXIhWKGXxkeNnq4TvV3CIOkUJ3PAoLZ3HMzNVMw=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
+        "type": "indirect"
+      }
+    },
     "nixpkgs-stable": {
       "locked": {
         "lastModified": 1643788601,
@@ -129,6 +195,7 @@
         "deploy-rs": "deploy-rs",
         "flake-utils": "flake-utils",
         "home-manager": "home-manager",
+        "nix": "nix",
         "nixpkgs-stable": "nixpkgs-stable",
         "nixpkgs-unstable": "nixpkgs-unstable"
       }