Add no-selection option to RMSD analysis

Author: ollyfutur

package/CHANGELOG

@@ -16,7 +16,7 @@ The rules for this file:
 -------------------------------------------------------------------------------
 ??/??/?? IAlibay, orbeckst, marinegor, tylerjereddy, ljwoods2, marinegor,
          spyke7, talagayev, tanii1125, BradyAJohnston, hejamu, jeremyleung521,
-         harshitgajjela-droid, kunjsinha, aygarwal, jauy123
+         harshitgajjela-droid, kunjsinha, aygarwal, jauy123, ollyfutur
 
  * 2.11.0
 
@@ -42,6 +42,7 @@ Fixes
    DSSP by porting upstream PyDSSP 0.9.1 fix (Issue #4913)
 
 Enhancements
+ * Allow `select=None` in `MDAnalysis.analysis.rms.RMSD`
  * Reduces duplication of code in _apply() function (Issue #5247, PR #5294)
  * Added new top-level `MDAnalysis.fetch` module (PR #4943)
  * Added new function `MDAnalysis.fetch.from_PDB` to download structure files from wwPDB