nix: Bump flake to get Rust 1.85 (#26076)

old nixpkgs versions didn't have rust 1.85 and nix develop failed (1.85
is specified in rust-toolchain.toml).

ran `nix flake update` to bump the flake dependencies. it now works

Release Notes:

- N/A

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "crane": {
       "locked": {
-        "lastModified": 1736898272,
-        "narHash": "sha256-D10wlrU/HCpSRcb3a7yk+bU3ggpMD1kGbseKtO+7teo=",
+        "lastModified": 1739936662,
+        "narHash": "sha256-x4syUjNUuRblR07nDPeLDP7DpphaBVbUaSoeZkFbGSk=",
         "owner": "ipetkov",
         "repo": "crane",
-        "rev": "6a589f034202a7c6e10bce6c5d1d392d7bc0f340",
+        "rev": "19de14aaeb869287647d9461cbd389187d8ecdb7",
         "type": "github"
       },
       "original": {
@@ -32,11 +32,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1737062831,
-        "narHash": "sha256-Tbk1MZbtV2s5aG+iM99U8FqwxU/YNArMcWAv6clcsBc=",
+        "lastModified": 1740695751,
+        "narHash": "sha256-D+R+kFxy1KsheiIzkkx/6L63wEHBYX21OIwlFV8JvDs=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "5df43628fdf08d642be8ba5b3625a6c70731c19c",
+        "rev": "6313551cd05425cd5b3e63fe47dbc324eabb15e4",
         "type": "github"
       },
       "original": {
@@ -61,11 +61,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1737166965,
-        "narHash": "sha256-vlDROBAgq+7PEVM0vaS2zboY6DXs3oKK0qW/1dVuFs4=",
+        "lastModified": 1740882709,
+        "narHash": "sha256-VC+8GxWK4p08jjIbmsNfeFQajW2lsiOR/XQiOOvqgvs=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "fc839c9d5d1ebc789b4657c43c4d54838c7c01de",
+        "rev": "f4d5a693c18b389f0d58f55b6f7be6ef85af186f",
         "type": "github"
       },
       "original": {