Update cisco-7200.gns3a

[Zero3Dash]

Adding addition 7200 series images (15.x version images)

Before submitting a pull request, please check the following.

---

When updating an existing appliance:

• [x] The new version is on top.
• [x] The filenames in the "images" section are unique, to avoid appliances / version overwriting each other.

• [ ] If you forked the repo, running check.py doesn't drop any errors for the updated file.

  When creating a new appliance:

• It's tested locally, i.e.
  • [x] You dragged an instance into a project on your box, got it installed (if necessary), and did some basic network checks (ping, UI reachable, etc.).
  • [x] GNS3 VM can run it without any tweaks.
  • [x] The device is in the right category: router, switch, guest (hosts), firewall
  • [x] You filled in as much info as possible (checks the schemas and other appliance files for some guidance).
• [ ] When adding a container: it builds on Docker Hub and can be pulled.
• [x] The filenames in the "images" section are unique (to avoid appliances and/or versions overwriting each other).
• [ ] If you forked the repo, running check.py doesn't drop any errors for the new file.
• [ ] Optional: a symbol has been created for the new appliance.

[eantowne]

@Zero3Dash, For your reference, should you submit another PR for a registry update:

• Please run python3 check.py in the repository root to validate the files
• When there is more than one version or image file version, it is necessary to have a , at the closing }, but not for the very last one. Example provided below.

Your submission:

"images": [
        {
            "filename": "c7200-adventerprisek9-mz.153-3.XB12.image",
            "version": "153-3.XB12",
            "md5sum": "3d234a3793331c972776354531f87221",
            "filesize": 131471340
        }
        {
            "filename": "c7200-advipservicesk9-mz.152-4.S5.image",
            "version": "152-4.S5",
            "md5sum": "cbbbea66a253f1dac0fcf81274dc778d",
            "filesize": 87756936
        }

Should have been:

"images": [
        {
            "filename": "c7200-adventerprisek9-mz.153-3.XB12.image",
            "version": "153-3.XB12",
            "md5sum": "3d234a3793331c972776354531f87221",
            "filesize": 131471340
        },
        {
            "filename": "c7200-advipservicesk9-mz.152-4.S5.image",
            "version": "152-4.S5",
            "md5sum": "cbbbea66a253f1dac0fcf81274dc778d",
            "filesize": 87756936
        }

This would also apply in the "versions" section.