Update minimum golang version to v1.23.9 (#3940)

Author: StephenButtolph

CONTRIBUTING.md

@@ -4,7 +4,7 @@
 
 To start developing on AvalancheGo, you'll need a few things installed.
 
-- Golang version >= 1.23.6
+- Golang version >= 1.23.9
 - gcc
 - g++
 

README.md

@@ -23,7 +23,7 @@ The minimum recommended hardware specification for nodes connected to Mainnet is
 
 If you plan to build AvalancheGo from source, you will also need the following software:
 
-- [Go](https://golang.org/doc/install) version >= 1.23.6
+- [Go](https://golang.org/doc/install) version >= 1.23.9
 - [gcc](https://gcc.gnu.org/)
 - g++
 

go.mod

@@ -7,7 +7,7 @@ module github.com/ava-labs/avalanchego
 //
 // - If updating between minor versions (e.g. 1.23.x -> 1.24.x):
 //   - Consider updating the version of golangci-lint (in scripts/lint.sh).
-go 1.23.6
+go 1.23.9
 
 require (
 	github.com/DataDog/zstd v1.5.2