tree-sitter-powershell: add build-tree-sitter-powershell.yml for riscv64 wheels

[luhenry]

• Package: tree-sitter-powershell
• Version: 0.26.4
• Source: https://github.com/airbus-cert/tree-sitter-powershell
• Docs: https://github.com/airbus-cert/tree-sitter-powershell

Compiles the PowerShell tree-sitter grammar's Python binding (a C extension over src/parser.c). Upstream publishes no riscv64 wheel.

Mirrors upstream's publish_pypi.yml, following the same shape already used for tree-sitter-json/tree-sitter-kotlin/tree-sitter-scala since the release tag commits a generated src/parser.c (no generate-then-build workaround needed, unlike tree-sitter-swift).

Differs from upstream

• Skips the tree-sitter generate regeneration step - the tagged src/parser.c already matches the tagged grammar.js.

Testing

• same as upstream

License: OK