Fix select bind incompatibility with H2 1.4.198

[pacphi]

Using r2dbc-h2-1.0.0.M7 I see that select bindings fail with

java.lang.NoSuchMethodError: org.h2.result.ResultInterface.getColumnType(I)I
    at io.r2dbc.h2.H2ColumnMetadata.toColumnMetadata(H2ColumnMetadata.java:127) ~[r2dbc-h2-1.0.0.M7.jar:na]
    at io.r2dbc.h2.H2RowMetadata.getColumnMetadatas(H2RowMetadata.java:106) ~[r2dbc-h2-1.0.0.M7.jar:na]
    at io.r2dbc.h2.H2RowMetadata.toRowMetadata(H2RowMetadata.java:99) ~[r2dbc-h2-1.0.0.M7.jar:na]
    at io.r2dbc.h2.H2Result.toResult(H2Result.java:86) ~[r2dbc-h2-1.0.0.M7.jar:na]

[sdeleuze]

Same issue with Boot 2.2 + r2dbc-h2 1.0.0.M6 which is using H2 1.4.198 by default.

[mp911de]

See also #9 (comment).

After discussing with H2 folks, the only stable H2 API is JDBC and H2 internals (used by r2dbc-h2) are always subject to change. So the best effort we can make is keeping up with H2 changes.