Shortest Path Error

**Describe the bug**

Neo4j is able to find the shortest path between nodes, but AGE fails to do so.

**How are you accessing AGE (Command line, driver, etc.)?**

AGE is run through docker (AGE 1.5.0) and accessed with psql.

**What data setup do we need to do?**

```pgsql
SELECT * FROM cypher('my_graph', $$
CREATE
(portia:Person {name: "Portia"}),
(bianca:Person {name: "Bianca"}),
(fabian:Person {name: "Fabian"})
CREATE
(bianca)-[:EDGE]->(portia),
(portia)-[:EDGE]->(fabian)
$$) as (v agtype);
```

**What is the necessary configuration info needed?**

Not applicable.

**What is the command that caused the error?**

```pgsql
SELECT * FROM cypher('my_graph', $$
MATCH p = SHORTEST 1 (a:Person {name: "Bianca"})-[r]-+(b:Person {name: "Fabian"})
RETURN nodes(p) as nodes
$$) AS (v agtype);
```

**Expected behaviour**

Neo4j outputs a list of nodes as expected (bianca -> portia -> fabian), but AGE throws the following error:

```
ERROR:  syntax error at or near "SHORTEST"
LINE 2:  MATCH p = SHORTEST 1 (a:Person {name: "Bianca"})-[r]-+(b:Pe...
                  ^
```

**Environment:**
- Version: 1.5.0

**Additional context**
Also tested through the python driver's `ag.execCypher` function.