feat: Require Go 1.26 and use new(expr) for pointer literals

[ajayk]

Bump go.mod to 1.26 per the N-1 support policy (Go 1.27 is current) and replace Ptr() with the new(v) builtin across tests.

[gmlewis]

@ajayk - please read step 4 of CONTRIBUTING.md and run the scripts locally to fix all test and linter errors, then push the changes to this PR before we can proceed.

[ajayk]

@ajayk - please read step 4 of CONTRIBUTING.md and run the scripts locally to fix all test and linter errors, then push the changes to this PR before we can proceed.

addressed them sorry about this !

➜  go-github git:(go-1.26) script/fmt.sh
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
WARN [formatter] gofumpt: `extra-rules` is deprecated, please use `extra.group-params` instead.
➜  go-github git:(go-1.26) script/test.sh
Testing modules

✔ .                                        [ PASS ]
✔ example                                  [ PASS ]
✔ otel                                     [ PASS ]
✔ scrape                                   [ PASS ]
✔ tools                                    [ PASS ]
✔ tools/check-structfield-settings         [ PASS ]
✔ tools/extraneousnew                      [ PASS ]
✔ tools/fmtpercentv                        [ PASS ]
✔ tools/paramcheck                         [ PASS ]
✔ tools/redundantptr                       [ PASS ]
✔ tools/sliceofpointers                    [ PASS ]
✔ tools/structfield                        [ PASS ]
----------------------------
Testing: issues found in 0 module directories.
--------------------------------------------
➜  go-github git:(go-1.26) script/lint.sh
Linting modules

✔ .                                        [ PASS ]
✔ example                                  [ PASS ]
✔ otel                                     [ PASS ]
✔ scrape                                   [ PASS ]
✔ tools                                    [ PASS ]
✔ tools/check-structfield-settings         [ PASS ]
✔ tools/extraneousnew                      [ PASS ]
✔ tools/fmtpercentv                        [ PASS ]
✔ tools/paramcheck                         [ PASS ]
✔ tools/redundantptr                       [ PASS ]
✔ tools/sliceofpointers                    [ PASS ]
✔ tools/structfield                        [ PASS ]
Validating generated files

✔ Generated files are up to date
----------------------------
Linting: issues found in 0 module directories.
--------------------------------------------

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 98.51%. Comparing base (30af001) to head (5f86d04).

Files with missing lines	Patch %	Lines
github/github.go	60.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4481      +/-   ##
==========================================
- Coverage   98.51%   98.51%   -0.01%     
==========================================
  Files         195      195              
  Lines       17691    17685       -6     
==========================================
- Hits        17429    17423       -6     
  Misses        262      262              

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[gmlewis]

I'm surprised the the Codecov report actually dropped in with this PR, but the bulk of the changes are for deprecated functions that are fixed with go:fix anyway, so I think we can safely ignore Codecov for this PR.

[gmlewis]

Thank you, @ajayk!
LGTM.
Awaiting second LGTM+Approval from any other contributor to this repo before merging.

cc: @stevehipwell - @alexandear - @Not-Dhananjay-Mishra