nix: update flakes to get a nixpkgs version with go 1.26

We override 1.26, but its not in the old commit we are tracking.

Updates #18682

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

flake.lock

@@ -3,11 +3,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1696426674,
-        "narHash": "sha256-kvjfFW7WAETZlt09AgDn1MrtKzP7t90Vf7vypd3OL1U=",
+        "lastModified": 1767039857,
+        "narHash": "sha256-vNpUSpF5Nuw8xvDLj2KCwwksIbjua2LZCqhV1LNRDns=",
         "owner": "edolstra",
         "repo": "flake-compat",
-        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
+        "rev": "5edf11c44bc78a0d334f6334cdaf7d60d732daab",
         "type": "github"
       },
       "original": {
@@ -18,11 +18,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1753151930,
-        "narHash": "sha256-XSQy6wRKHhRe//iVY5lS/ZpI/Jn6crWI8fQzl647wCg=",
+        "lastModified": 1772736753,
+        "narHash": "sha256-au/m3+EuBLoSzWUCb64a/MZq6QUtOV8oC0D9tY2scPQ=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "83e677f31c84212343f4cc553bab85c2efcad60a",
+        "rev": "917fec990948658ef1ccd07cef2a1ef060786846",
         "type": "github"
       },
       "original": {