Transform Pandas DataFrame, add row values as column headers

I think you need set_index + unstack:

df = df.set_index(['COMMIT_ID','COMMITTER','FILE_NAME'])['CHANGE TYPE']
       .unstack()
      .reset_index()
print (df)
FILE_NAME  COMMIT_ID COMMITTER class.java main.js package.json
0                  1         A       None    None       MODIFY
1                  2         B     DELETE     ADD         None

Solutions with pivot_table - need aggregate function like sum (concatenate strings without separator) or '_'.join (concatenate strings with separator) if duplicates:

print (df)
   COMMIT_ID     FILE_NAME COMMITTER CHANGE TYPE
0          1  package.json         A      MODIFY
1          2       main.js         B         ADD
2          2    class.java         B      DELETE
3          2    class.java         B         ADD


df = df.pivot_table(index=['COMMIT_ID','COMMITTER'], 
                    columns='FILE_NAME', 
                    values='CHANGE TYPE', 
                    aggfunc='sum').reset_index()
print (df)
FILE_NAME  COMMIT_ID COMMITTER class.java main.js package.json
0                  1         A       None    None       MODIFY
1                  2         B  DELETEADD     ADD         None

Or:

df = df.pivot_table(index=['COMMIT_ID','COMMITTER'], 
                    columns='FILE_NAME', 
                    values='CHANGE TYPE', 
                    aggfunc='_'.join).reset_index()
print (df)
FILE_NAME  COMMIT_ID COMMITTER  class.java main.js package.json
0                  1         A        None    None       MODIFY
1                  2         B  DELETE_ADD     ADD         None

Aggregate with first works also, but you can lost duplicates values:

df = df.pivot_table(index=['COMMIT_ID','COMMITTER'], 
                    columns='FILE_NAME', 
                    values='CHANGE TYPE', 
                    aggfunc='first').reset_index()
print (df)
FILE_NAME  COMMIT_ID COMMITTER class.java main.js package.json
0                  1         A       None    None       MODIFY
1                  2         B     DELETE     ADD         None

Last for rename columns names add rename_axis:

df = df.rename_axis(None, axis=1)
print (df)
   COMMIT_ID COMMITTER class.java main.js package.json
0          1         A       None    None       MODIFY
1          2         B  DELETEADD     ADD         None