Fix tree vine on dependency group line

[stephaneyfx]

The indentation was off. Tested on Linux. I don't have a Mac to test.
Before:

2/2        75/75        4/4    1/1     1/1      !  ├── petgraph 0.5.1
0/0        62/62        0/0    0/0     0/0      !  │   ├── fixedbitset 0.2.0
0/0        88/93        1/1    0/0     2/2      !  │   └── indexmap 1.5.0
2/2        954/1048     16/19  0/0     34/38    !  │       └── hashbrown 0.8.1
                                                  │           [build-dependencies]
0/0        0/0          0/0    0/0     0/0      ?  │           └── autocfg 1.0.0
                                                  │       [build-dependencies]
0/0        0/0          0/0    0/0     0/0      ?  │       └── autocfg 1.0.0

After:

2/2        75/75        4/4    1/1     1/1      !  ├── petgraph 0.5.1
0/0        62/62        0/0    0/0     0/0      !  │   ├── fixedbitset 0.2.0
0/0        88/93        1/1    0/0     2/2      !  │   └── indexmap 1.5.0
2/2        954/1048     16/19  0/0     34/38    !  │       └── hashbrown 0.8.1
                                                   │           [build-dependencies]
0/0        0/0          0/0    0/0     0/0      ?  │           └── autocfg 1.0.0
                                                   │       [build-dependencies]
0/0        0/0          0/0    0/0     0/0      ?  │       └── autocfg 1.0.0

[anderejd]

Tested on macOS just now. I can observe the bug in the master branch and this PR fixes the problem, thanks! 👍