Powershell Increment value by 0.0.1

Convert to a [version] object:

# read existing version
$version = [version](Get-Content 'package.json' | ConvertFrom-Json).version

# create new version based on previous with Build+1
$bumpedVersion = [version]::new($version.Major, $version.Minor, $Version.Build + 1)

Alternatively, split the string manually:

$major,$minor,$build = $version.Split('.')

# increment build number
$build = 1 + $build

# stitch back together
$bumpedVersion = $major,$minor,$build -join '.'

To complement Mathias' helpful answer with a concise alternative based on the -replace operator:

# PowerShell [Core] only (v6.2+) - see bottom for Windows PowerShell solution.
PS> '0.0.3', '1.123.3' -replace '(?<=\.)[^.]+$', { 1 + $_.Value }
0.0.4
1.123.4

• Regex (?<=\.)[^.]+$ matches the last component of the version number (without including the preceding . in the match).

• Script block { 1 + $_.Value } replaces that component with its value incremented by 1.

For solutions to incrementing any of the version-number components, including proper handling of [semver] version numbers, see this answer.

In Windows PowerShell, where the script-block-based -replace syntax isn't supported, the solution is more cumbersome, because it requires direct use of the .NET System.Text.RegularExpressions.Regex type:

PS> '0.0.3', '1.123.3' | foreach { 
       [regex]::Replace($_, '(?<=\.)[^.]+$', { param($m) 1 + $m.Value })
    }
0.0.4
1.123.4

C:\> $v = "1.2.3"
C:\> $(($v -split "\.")[0..1] + "$([int](($v -split '\.') |Select-Object -Index 2) +1)") -join "."

Try this:

$build = [int]($version.split(".")[2])+1
$bumpedversion = $version.split(".")[0], $version.split(".")[1], $build -join "."