Change io_service to io_context

This was renamed a while back in boost to be compliant with the
std::executors proposal.

Change-Id: Ib56544a0a7478990d18fe9e0bbbd8db1e52fa5b8
Signed-off-by: Ed Tanous <edtanous@google.com>
diff --git a/src/TachSensor.cpp b/src/TachSensor.cpp
index 9a1ff7c..0462186 100644
--- a/src/TachSensor.cpp
+++ b/src/TachSensor.cpp
@@ -44,7 +44,7 @@
                        std::shared_ptr<sdbusplus::asio::connection>& conn,
                        std::unique_ptr<PresenceSensor>&& presenceSensor,
                        std::optional<RedundancySensor>* redundancy,
-                       boost::asio::io_service& io, const std::string& fanName,
+                       boost::asio::io_context& io, const std::string& fanName,
                        std::vector<thresholds::Threshold>&& thresholdsIn,
                        const std::string& sensorConfiguration,
                        const std::pair<double, double>& limits,
@@ -210,7 +210,7 @@
 }
 
 PresenceSensor::PresenceSensor(const std::string& gpioName, bool inverted,
-                               boost::asio::io_service& io,
+                               boost::asio::io_context& io,
                                const std::string& name) :
     gpioLine(gpiod::find_line(gpioName)),
     gpioFd(io), name(name)