Update version number to 1.20190419.0-develop
Update version number to 1.20190419.0-develop

rachel-fenichel/blockly,picklesrus/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,google/blockly,nickmain/blockly,joshlory/blockly,joshlory/blockly,rachel-fenichel/blockly,google/blockly,google/blockly,rachel-fenichel/blockly,nickmain/blockly,picklesrus/blockly,nickmain/blockly,google/blockly,rachel-fenichel/blockly,nickmain/blockly,mark-friedman/blockly,google/blockly,rachel-fenichel/blockly,mark-friedman/blockly,mark-friedman/blockly,picklesrus/blockly,nickmain/blockly,joshlory/blockly,mark-friedman/blockly,nickmain/blockly,google/blockly,mark-friedman/blockly,google/blockly,mark-friedman/blockly