Update src/tar.ts

Co-authored-by: Andrew Eisenberg <aeisenberg@github.com>

src/tar.ts

@@ -97,7 +97,7 @@ export async function isZstdAvailable(
  }
  } catch (e) {
  logger.warning(
- "Failed to determine tar version, therefore will assume zstd may not be available. " +
+ "Failed to determine tar version, therefore will assume zstd is not available. " +
  `The underlying error was: ${e}`,
  );
  return { available: false, foundZstdBinary };