Upgrade to R2DBC SPI 0.9.1.

[resolves #178]

Signed-off-by: Mark Paluch <mpaluch@vmware.com>

pom.xml

@@ -41,7 +41,7 @@
         <mockito.version>4.7.0</mockito.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-        <r2dbc-spi.version>0.9.0.RELEASE</r2dbc-spi.version>
+        <r2dbc-spi.version>0.9.1.RELEASE</r2dbc-spi.version>
         <reactor.version>2020.0.22</reactor.version>
     </properties>