chore: bump version to v1.0.0 (#155)

Our next release will be v1.0.0 as part of our adherence to
semantic versioning (semver). While there are no major changes,
commits 32f0338 and d354e96 introduced some API changes that
are not backward-compatible.

Author: dmehala

src/datadog/version.cpp

@@ -3,7 +3,7 @@
 namespace datadog {
 namespace tracing {
 
-#define DD_TRACE_VERSION "v0.2.2"
+#define DD_TRACE_VERSION "v1.0.0"
 
 const char* const tracer_version = DD_TRACE_VERSION;
 const char* const tracer_version_string =