Update local clone and default branch on GitHub

UpdateEverything.ps1

function Update-GitDefaultBranch
{
    [CmdletBinding()]
    param
    (
        # Base path where you store all your repos...
        [Parameter(Mandatory)]
        [string]
        $Path,

        # your GitHub Username and a Personal Access Token
        [Parameter(Mandatory)]
        [pscredential]
        $Credential,
    
        # a filtering script block to filter on specific repos, e.g. $_.name -like '*thing*'
        [Parameter()]
        [scriptblock]
        $RepoFilter = { -not $_.fork },

        [Parameter()]
        [string]
        $OldBranchName = 'master',

        [Parameter(Mandatory)]
        [string]
        $NewBranchName,

        # Indicate that the default branch should only be changed if the local clone has been updated first
        [switch]
        $RequireLocalUpdate
    )

    if ($RequireLocalUpdate.IsPresent -and -not (Get-Command git))
    {
        Write-Warning -Message 'No git binary found while RequireLocalUpdate is used.'
        return
    }
    $tokenString = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $credential.UserName, $credential.GetNetworkCredential().Password)))

    # The header is simply a hashtable with whatever headers you need
    $header = @{
        Authorization = 'Basic {0}' -f $tokenString
    }

    $repos = Invoke-RestMethod -Method Get -Uri "https://api.github.com/users/$($credential.UserName)/repos?type=owner&per_page=1000" -ErrorVariable octoError -Headers $header
    if ($octoError)
    {
        return
    }

    foreach ($repo in $repos.Where($RepoFilter))
    {
        if (Test-Path -Path (Join-Path -Path $Path -ChildPath $repo.name))
        {
            Push-Location
            Set-Location -Path (Join-Path -Path $Path -ChildPath $repo.name)
            $localUpdateOk = $true
            $stuff = git branch -m $OldBranchName $NewBranchName 2>&1
            if ($LASTEXITCODE -ne 0)
            {
                Write-Error -Message ('Unable to update {0} to {1}. Git output {2}' -f $OldBranchName, $NewBranchName, $stuff )
                $localUpdateOk = $false
            }
            $stuff = git push -u origin $NewBranchName 2>&1
            if ($LASTEXITCODE -ne 0)
            {
                Write-Error -Message ('Unable to push change to origin. Git output {0}' -f $stuff )
                $localUpdateOk = $false   
            }
            Pop-Location
        }

        if ($repo.default_branch -eq $OldBranchName -and (-not $RequireLocalUpdate.IsPresent -or $RequireLocalUpdate.IsPresent -and $localUpdateOk))
        {
            $patchParam = @{
                default_branch = $NewBranchName
            } | ConvertTo-Json
            Invoke-RestMethod -Method Patch -Uri $repo.url -Body $patchParam -ContentType application/json -Headers $header
        }
    }
}

Update-GitDefaultBranch -Path $Home/source/repos -Credential (Get-Credential) -OldBranchName master -NewBranchName mimir -RequireLocalUpdate -RepoFilter {$_.name -ne 'ExeWrapper' -and -not $_.fork}