Create a new version of imdb.csv and update the examples to use it

[tatiana]

Context

Our smallest example of the Astro SDK uses the imdb.csv dataset, which currently has capitalized columns. It works fine for the illustrative example (Sqlite), but when using Postgres, the same transform select statement fails.

Example DAG

@aql.transform()
def get_top_ten_rated_films(input_table: Table):
    return """
            SELECT Title, Rating, Genre
            FROM {{ input_table }}
            ORDER BY Rating DESC
            LIMIT 10;
        """

with DAG(...):
    load_imdb_movies = aql.load_file(
        task_id='load_imdb_movies',
        input_file=File(
            path='https://raw.githubusercontent.com/astronomer/astro-sdk/main/tests/data/imdb.csv'
        ),
        output_table=Table(
            name='imdb_movies',
            conn_id=CONN_ID,
        ),
    )

    top_ten_rated_films = get_top_ten_rated_films(
        input_table=load_imdb_movies,
        output_table=Table(
            name='top_rated',
            conn_id=CONN_ID,
        ),
    )

The issue raised:

[2022-08-23, 10:17:35 UTC] {taskinstance.py:1910} ERROR - Task failed with exception
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 1705, in _execute_context
    self.dialect.do_execute(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 716, in do_execute
    cursor.execute(statement, parameters)
psycopg2.errors.UndefinedColumn: column "title" does not exist
LINE 2:             SELECT Title, Rating, Genre
                           ^
HINT:  Perhaps you meant to reference the column "imdb_movies.Title".

The workaround is to change the select statement:

            SELECT "Title", "Rating", "Genre"

Acceptance criteria

• Create a new version of imdb.csv with lowercase column names and update the examples to use it, so this change is backwards-compatible