bump the minimum disk size

"Not enough disk space"

    Warning ProvisioningFailed 24m (x12 over 25m)
    rawfile.csi.openebs.io_ck-storage-rawfile-csi-node-4jj4x_8ffe9da2-1b1b-4170-bd00-784420373e61
    failed to provision volume with StorageClass "csi-rawfile-default":
    rpc error: code = ResourceExhausted desc = Not enough disk space

.github/workflows/single-node-guided.yml

@@ -51,7 +51,8 @@ jobs:
                   # https://canonical.com/microstack/docs/single-node-guided
                   echo CPU=4             >> "$GITHUB_ENV"
                   echo MEMORY=16         >> "$GITHUB_ENV"
-                  echo DISK=50           >> "$GITHUB_ENV"
+                  # LP: #2098076
+                  echo DISK=100          >> "$GITHUB_ENV"
               ;;
               *)
                   echo '::error:: Invalid hardware profile'