fix(abacus): fix bug in read LATTICE_CONSTANT in md

[pxlxingliang]

In ABACUS version >= v3.1.4, the format of file "MD_dump" is different. The lattice constant line is added by the unit "Angstrom" at the end, and the position is the real cartesian coordinate.
MD_dump is changed from

MDSTEP:  0
LATTICE_CONSTANT: 23.453780000000
LATTICE_VECTORS
  1.000000000000  0.000000000000  0.000000000000
  0.000000000000  1.000000000000  0.000000000000
  0.000000000000  0.000000000000  1.000000000000
VIRIAL (KBAR)
  36.689617311102  0.000000000001  -0.000000000000
  0.000000000001  36.689617311104  -0.000000000001
  -0.000000000000  -0.000000000001  36.689617311147
INDEX    LABEL    POSITIONS    FORCE (eV/Angstrom)
  0  Sn  0.000000000000  0.000000000000  0.000000000000  -0.000000000000  0.000000000000  -0.000000000000
  1  Sn  0.000000000000  0.250000000000  0.250000000000  -0.000186795145  -0.000453823732  -0.000453823732

to

MDSTEP:  0
LATTICE_CONSTANT: 12.411200939060 Angstrom
LATTICE_VECTORS
  1.000000000000  0.000000000000  0.000000000000
  0.000000000000  1.000000000000  0.000000000000
  0.000000000000  0.000000000000  1.000000000000
VIRIAL (kbar)
  36.689617311101  0.000000000003  -0.000000000000
  0.000000000003  36.689617311089  -0.000000000001
  -0.000000000000  -0.000000000001  36.689617311135
INDEX    LABEL    POSITION (Angstrom)    FORCE (eV/Angstrom)    VELOCITY (Angstrom/fs)
  0  Sn  0.000000000000  0.000000000000  0.000000000000  -0.000000000000  -0.000000000001  -0.000000000001  0.001244557166  -0.000346684288  0.000768457739
  1  Sn  0.000000000000  3.102800034079  3.102800034079  -0.000186795145  -0.000453823768  -0.000453823768  0.000550996187  -0.000886442775  0.001579501983

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.05 🎉

Comparison is base (6232559) 82.49% compared to head (f3fc1fc) 82.55%.

Additional details and impacted files

@@            Coverage Diff             @@
##            devel     #450      +/-   ##
==========================================
+ Coverage   82.49%   82.55%   +0.05%     
==========================================
  Files          68       68              
  Lines        6193     6196       +3     
==========================================
+ Hits         5109     5115       +6     
+ Misses       1084     1081       -3     

Impacted Files	Coverage Δ
dpdata/abacus/md.py	99.17% <100.00%> (+0.02%)	⬆️

... and 1 file with indirect coverage changes

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[pxlxingliang]

@njzjz fix the bug in reading lattice constant and coordinate, and add unittest for new version.

[njzjz]

We follow numpydoc to use docstring as documentation. Please do not leave raw data in the docstring.

[pxlxingliang]

Ok, it is removed.

[AnguseZhang]

@pxlxingliang Is this patch compatible with the version older than 3.1.4?

[pxlxingliang]

Yes，it is compatible

[pxlxingliang]

@njzjz @wanghan-iapcm，please help check this PR. If there is no problem, please help merge it as soon as possible. This bug has a significant effect on the using of dpdata+ABACUS. Besides, I hope a new version to be relased after this PR is merged.