update nixpkgs

Includes
- update stable
- btcpayserver: 1.2.4 -> 1.3.1
- electrs: 0.9.1 -> 0.9.2
- nbxplorer: 2.2.11 -> 2.2.16

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "flake-utils": {
       "locked": {
-        "lastModified": 1631561581,
-        "narHash": "sha256-3VQMV5zvxaVLvqqUrNz3iJelLw30mIVSfZmAaauM3dA=",
+        "lastModified": 1634851050,
+        "narHash": "sha256-N83GlSGPJJdcqhUxSCS/WwW5pksYf3VP1M13cDRTSVA=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "7e5bf3925f6fbdfaf50a2a7ca0be2879c4261d19",
+        "rev": "c91f3de5adaf1de973b797ef7485e441a65b8935",
         "type": "github"
       },
       "original": {
@@ -17,11 +17,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1633422542,
-        "narHash": "sha256-JYz2PmVogNRO8DhcvXzL/QhZzboTspJz2YSRlnAj8aM=",
+        "lastModified": 1635719588,
+        "narHash": "sha256-pWjdy0NheM97NsPE6+jUnr5LYyeA0sBGTdw4mfXMGZQ=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "aff647e2704fa1223994604887bb78276dc57083",
+        "rev": "f0869b1a2c0b150aac26e10bb5c2364ffb2e804f",
         "type": "github"
       },
       "original": {
@@ -33,11 +33,11 @@
     },
     "nixpkgsUnstable": {
       "locked": {
-        "lastModified": 1635295995,
-        "narHash": "sha256-sGYiXjFlxTTMNb4NSkgvX+knOOTipE6gqwPUQpxNF+c=",
+        "lastModified": 1635781173,
+        "narHash": "sha256-nTA2y2jIJiVj5RawHUNhlZUIy5J/Q2CA6YP4T1qBkLo=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "22a500a3f87bbce73bd8d777ef920b43a636f018",
+        "rev": "7053541084bf5ce2921ef307e5585d39d7ba8b3f",
         "type": "github"
       },
       "original": {