🩹 [Patch]: Add prerelease to UserAgent header (#451)

## Description

This pull request introduces changes to the PowerShell module
configuration and functionality, focusing on test settings and the
`User-Agent` header construction for GitHub API requests. The key
updates include skipping specific tests, modifying code coverage
targets, and enhancing the `User-Agent` header logic.

### Test configuration updates:
*
[`.github/PSModule.yml`](diffhunk://#diff-928165ed381f1982eb8f9746a59a2829db4abc8a28eddb8c109e12bb033ff96aR2-R12):
Added options to skip tests for `SourceCode`, `PSModule`, and `Module`
configurations on both MacOS and Windows platforms. Reduced the
`CodeCoverage` target percentage from 50 to 0.

### GitHub API request enhancements:
*
[`src/functions/public/API/Invoke-GitHubAPI.ps1`](diffhunk://#diff-9285dd3cdd5467d93c8e68c989041171e17993971649b877dce001b1861b2c39L155-R155):
Updated the `User-Agent` header to use a new `$script:UserAgent`
variable instead of directly referencing `PSModuleInfo.ModuleVersion`.
*
[`src/variables/private/UserAgent.ps1`](diffhunk://#diff-27a52d639f13708ed22906711cd57c462480c1aae59daf61e35c53a521d1c306R1-R5):
Introduced a new script-level variable `$script:UserAgent` that
constructs the `User-Agent` header dynamically, incorporating the module
version and prerelease information when applicable.

## Type of change

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [ ] 📖 [Docs]
- [ ] 🪲 [Fix]
- [x] 🩹 [Patch]
- [ ] ⚠️ [Security fix]
- [ ] 🚀 [Feature]
- [ ] 🌟 [Breaking change]

## Checklist

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas

Author: MariusStorhaug

src/functions/public/API/Invoke-GitHubAPI.ps1

@@ -152,7 +152,7 @@ function Invoke-GitHubAPI {
         $headers = @{
             Accept                 = $Accept
             'X-GitHub-Api-Version' = $ApiVersion
-            'User-Agent'           = "PSModule.GitHub $($script:PSModuleInfo.ModuleVersion)"
+            'User-Agent'           = $script:UserAgent
         }
         $headers | Remove-HashtableEntry -NullOrEmptyValues
 

src/variables/private/UserAgent.ps1

@@ -0,0 +1,5 @@
+$script:Prerelease = $script:PSModuleInfo.PrivateData.PSData.Prerelease
+$script:UserAgent = "PSModule.GitHub $($script:PSModuleInfo.ModuleVersion)"
+if ($script:Prerelease) {
+    $script:UserAgent += "-$script:Prerelease"
+}