fix(deps): update dependency ethers to v6.15.0

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package.json

@@ -9,7 +9,7 @@
     "@celo/abis": "^10.0.0",
     "@celo/identity": "^5.1.1",
     "dotenv": "^16.4.1",
-    "ethers": "6.13.4",
+    "ethers": "6.15.0",
     "viem": "^1.19.9"
   }
 }

yarn.lock

@@ -2598,10 +2598,10 @@ ethereumjs-util@^7.1.0, ethereumjs-util@^7.1.1, ethereumjs-util@^7.1.2, ethereum
     ethereum-cryptography "^0.1.3"
     rlp "^2.2.4"
 
-ethers@6.13.4:
-  version "6.13.4"
-  resolved "https://registry.yarnpkg.com/ethers/-/ethers-6.13.4.tgz#bd3e1c3dc1e7dc8ce10f9ffb4ee40967a651b53c"
-  integrity sha512-21YtnZVg4/zKkCQPjrDj38B1r4nQvTZLopUGMLQ1ePU2zV/joCfDC3t3iKQjWRzjjjbzR+mdAIoikeBRNkdllA==
+ethers@6.15.0:
+  version "6.15.0"
+  resolved "https://registry.yarnpkg.com/ethers/-/ethers-6.15.0.tgz#2980f2a3baf0509749b7e21f8692fa8a8349c0e3"
+  integrity sha512-Kf/3ZW54L4UT0pZtsY/rf+EkBU7Qi5nnhonjUb8yTXcxH3cdcWrV2cRyk0Xk/4jK6OoHhxxZHriyhje20If2hQ==
   dependencies:
     "@adraffy/ens-normalize" "1.10.1"
     "@noble/curves" "1.2.0"