go: bump to 1.26 (#612)

README.md

diff --git a/README.md b/README.md
index 2b0a33e..887e879 100644
--- a/README.md
+++ b/README.md
@@ -14,8 +14,6 @@
 
 This library is built in Go, and uses the [support policy](https://golang.org/doc/devel/release.html#policy) of Go as its support policy. The two latest major releases of Go are supported by terraform-exec.
 
-Currently, that means Go **1.24** or later must be used.
-
 ## Terraform compatibility
 
 We generally follow [Terraform's own compatibility promises](https://developer.hashicorp.com/terraform/language/v1-compatibility-promises). i.e. **we recommend Terraform v1.x to be used alongside this library**.

go.mod

diff --git a/go.mod b/go.mod
index c14595b..29b7d8f 100644
--- a/go.mod
+++ b/go.mod
@@ -1,9 +1,9 @@
 module github.com/hashicorp/terraform-exec
 
 // Keep last digit at zero, use toolchain for Go build requirement
-go 1.25.0
+go 1.26.0
 
-toolchain go1.25.8
+toolchain go1.26.8
 
 require (
 	github.com/google/go-cmp v0.7.0