build(go): bump to 1.26.3 (#11850)

# Description

bump go to the latest one

## Type of change

- This pull request is a minor refactor, code cleanup, test improvement,
or other maintenance task and doesn't change the functionality of Radius
(issue link optional).

## Contributor checklist
Please verify that the PR meets the following requirements, where
applicable:

- An overview of proposed schema changes is included in a linked GitHub
issue.
    - [ ] Yes
    - [x] Not applicable
- A design document is added or updated under `eng/design-notes/` in
this repository, if new APIs are being introduced.
    - [ ] Yes
    - [x] Not applicable
- The design document has been reviewed and approved by Radius
maintainers/approvers.
    - [ ] Yes
    - [x] Not applicable
- A PR for
[resource-types-contrib](https://github.com/radius-project/resource-types-contrib/)
is created, if resource types or recipes are affected by the changes in
this PR.
    - [ ] Yes
    - [x] Not applicable
- A PR for [dashboard](https://github.com/radius-project/dashboard/) is
created, if the Radius Dashboard is affected by the changes in this PR.
    - [ ] Yes
    - [x] Not applicable
- A PR for the [documentation
repository](https://github.com/radius-project/docs) is created, if the
changes in this PR affect the documentation or any user facing updates
are made.
    - [ ] Yes
    - [x] Not applicable

Signed-off-by: Dariusz Porowski <3431813+DariuszPorowski@users.noreply.github.com>

Author: DariuszPorowski

go.mod

@@ -1,6 +1,6 @@
 module github.com/radius-project/radius
 
-go 1.26.1
+go 1.26.3
 
 // Replace digest lib to master to gather access to BLAKE3.
 // xref: https://github.com/opencontainers/go-digest/pull/66
@@ -68,6 +68,7 @@ require (
 	github.com/gosuri/uilive v0.0.4
 	github.com/hashicorp/go-getter v1.8.6
 	github.com/hashicorp/go-retryablehttp v0.7.8
+	github.com/hashicorp/go-version v1.9.0
 	github.com/hashicorp/hc-install v0.9.4
 	github.com/hashicorp/terraform-config-inspect v0.0.0-20250828155816-225c06ed5fd9
 	github.com/hashicorp/terraform-exec v0.25.1
@@ -117,8 +118,6 @@ require (
 	sigs.k8s.io/yaml v1.6.0
 )
 
-require github.com/hashicorp/go-version v1.9.0
-
 require (
 	cel.dev/expr v0.25.1 // indirect
 	cloud.google.com/go v0.123.0 // indirect