string: ensure string included

Latest upstream yocto appears to have removed a free include of string.
This is causing compile failures for files which do not include it
properly.

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: Ic1bf10e15071227582e5738336f632d33705c80b
diff --git a/activation.hpp b/activation.hpp
index 343458d..41ff1cd 100644
--- a/activation.hpp
+++ b/activation.hpp
@@ -8,6 +8,7 @@
 #include "xyz/openbmc_project/Software/RedundancyPriority/server.hpp"
 
 #include <sdbusplus/server.hpp>
+#include <string>
 #include <xyz/openbmc_project/Association/Definitions/server.hpp>
 #include <xyz/openbmc_project/Software/Activation/server.hpp>
 #include <xyz/openbmc_project/Software/ActivationBlocksTransition/server.hpp>
diff --git a/image_verify.hpp b/image_verify.hpp
index 0aff4b8..d4f0930 100644
--- a/image_verify.hpp
+++ b/image_verify.hpp
@@ -9,6 +9,7 @@
 
 #include <experimental/filesystem>
 #include <set>
+#include <string>
 
 namespace openpower
 {
diff --git a/item_updater.hpp b/item_updater.hpp
index 3a00afe..33dc05b 100644
--- a/item_updater.hpp
+++ b/item_updater.hpp
@@ -5,6 +5,7 @@
 #include "xyz/openbmc_project/Collection/DeleteAll/server.hpp"
 
 #include <sdbusplus/server.hpp>
+#include <string>
 #include <xyz/openbmc_project/Association/Definitions/server.hpp>
 #include <xyz/openbmc_project/Common/FactoryReset/server.hpp>
 #include <xyz/openbmc_project/Object/Enable/server.hpp>
diff --git a/static/activation_static.hpp b/static/activation_static.hpp
index 258a612..8cf563c 100644
--- a/static/activation_static.hpp
+++ b/static/activation_static.hpp
@@ -3,6 +3,7 @@
 #include "activation.hpp"
 
 #include <filesystem>
+#include <string>
 
 namespace openpower
 {
diff --git a/static/item_updater_static.hpp b/static/item_updater_static.hpp
index 40f616b..ce50462 100644
--- a/static/item_updater_static.hpp
+++ b/static/item_updater_static.hpp
@@ -2,6 +2,8 @@
 
 #include "item_updater.hpp"
 
+#include <string>
+
 namespace openpower
 {
 namespace software
diff --git a/ubi/activation_ubi.hpp b/ubi/activation_ubi.hpp
index a6ef436..957ee06 100644
--- a/ubi/activation_ubi.hpp
+++ b/ubi/activation_ubi.hpp
@@ -2,6 +2,8 @@
 
 #include "activation.hpp"
 
+#include <string>
+
 namespace openpower
 {
 namespace software
diff --git a/ubi/item_updater_ubi.hpp b/ubi/item_updater_ubi.hpp
index 183daac..ccd8e57 100644
--- a/ubi/item_updater_ubi.hpp
+++ b/ubi/item_updater_ubi.hpp
@@ -2,6 +2,8 @@
 
 #include "item_updater.hpp"
 
+#include <string>
+
 namespace openpower
 {
 namespace software
diff --git a/ubi/watch.hpp b/ubi/watch.hpp
index 4d195a3..2e0ec17 100644
--- a/ubi/watch.hpp
+++ b/ubi/watch.hpp
@@ -5,6 +5,7 @@
 
 #include <functional>
 #include <memory>
+#include <string>
 
 namespace openpower
 {
diff --git a/utils.hpp b/utils.hpp
index 9d119b3..6bd8d97 100644
--- a/utils.hpp
+++ b/utils.hpp
@@ -8,6 +8,7 @@
 #include <openssl/evp.h>
 
 #include <sdbusplus/bus.hpp>
+#include <string>
 
 extern "C" {
 EVP_MD_CTX* EVP_MD_CTX_new(void);
diff --git a/version.hpp b/version.hpp
index 85dccda..c7d2b03 100644
--- a/version.hpp
+++ b/version.hpp
@@ -7,6 +7,7 @@
 #include "xyz/openbmc_project/Software/Version/server.hpp"
 
 #include <sdbusplus/bus.hpp>
+#include <string>
 
 namespace openpower
 {