Make version flag optional [main]

[gururajsh]

Make the --version flag for revision command optional. When no version flag is provided, all the deployed revisions are displayed.

For ex, if we have the an app named dora and we run revision command without version flag, only deployed revision is displayed.

% cf revisions dora
Getting revisions for app dora in org o / space s as admin...

revision      description             deployable   revision guid                          created at
2(deployed)   New droplet deployed.   true         4b688a00-1b3a-415e-8530-4a0820757fc0   2025-01-13T15:05:38Z
1             Initial revision.       true         e931320d-9ef7-46a9-be1d-d3d78648ea04   2025-01-13T15:04:21Z

% cf revision dora
Showing revisions for app dora in org o / space s as admin...

revision:        2
deployed:        true
description:     New droplet deployed.
deployable:      true
revision GUID:   4b688a00-1b3a-415e-8530-4a0820757fc0
droplet GUID:    a2f451cc-3d7d-4c34-9e49-ef56db18ebb9
created on:      2025-01-13T15:05:38Z

labels:
annotations:
application environment variables:

[a-b]

LGTM

[joaopapereira]

The PR looks good, but I think we should do the optimization I commented about.

[joaopapereira]

After talking about my previous point @gururajsh pointed out that the result was behind used in the other if so LGTM