Naive glob to regex. Does not work for 🌈 and 🦄

GlobToRegex.ps1

function Convert-GlobToRegex([string] $pattern)
{
    $regex = $pattern -replace '\*\*(/|\\)', '🌈' `
        -replace '\\', '\\' `
        -replace '\*\*', '🦄' `
        -replace '\*', '[^/\\]*' `
        -replace '\.', '\.' `
        -replace '🌈', '(.*(/|\\))?' `
        -replace '🦄', '.*'

    "^$regex$"
}