fix: usage names install.py, not its copy

install.ps1 runs a copy named retrobios-install-<guid>.py, and --help and
every usage error printed that name. The parser names install.py.

install/launchers/index.json

@@ -27,8 +27,8 @@
         {
           "dest": "roms/ports/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 910604,
-          "sha256": "d3900f45996c1df29734403c5d15767c5fc3badcb070c93bbaf5a4f16f65140b",
+          "size": 910769,
+          "sha256": "4464cd84fdc1fcabb2428d73a9e5c1842e16f81d62b6e016d01a3408c8d41d67",
           "executable": false
         },
         {
@@ -71,8 +71,8 @@
     "muos": {
       "archive": {
         "dest": "ARCHIVE/RetroBIOS.muxapp",
-        "size": 963396,
-        "sha256": "adb57fcae73e5138cc204f38065557677fe32cd11888e336cd1363eb53d72b20"
+        "size": 963561,
+        "sha256": "122336a78dc618927fc75c708c2991ae373783db031e3fba5828bc372e17e3f8"
       },
       "members": [
         {
@@ -92,8 +92,8 @@
         {
           "name": "RetroBIOS/install.py",
           "repo_path": "install.py",
-          "size": 910604,
-          "sha256": "d3900f45996c1df29734403c5d15767c5fc3badcb070c93bbaf5a4f16f65140b",
+          "size": 910769,
+          "sha256": "4464cd84fdc1fcabb2428d73a9e5c1842e16f81d62b6e016d01a3408c8d41d67",
           "executable": false
         },
         {
@@ -166,8 +166,8 @@
         {
           "dest": ".config/modules/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 910604,
-          "sha256": "d3900f45996c1df29734403c5d15767c5fc3badcb070c93bbaf5a4f16f65140b",
+          "size": 910769,
+          "sha256": "4464cd84fdc1fcabb2428d73a9e5c1842e16f81d62b6e016d01a3408c8d41d67",
           "executable": false
         },
         {