Correcting image in Flow page of Mapper

 Correcting Flow image in mapper documentation

Change-Id: I4839d1e52e2c121fa8dfa7d5b99f08cb08247d8d
Issue-ID: DCAEGEN2-936
Signed-off-by: Pooja03 <pm00501616@techmahindra.com>

diff --git a/docs/sections/services/mapper/flow.PNG b/docs/sections/services/mapper/flow.png
similarity index 100%
rename from docs/sections/services/mapper/flow.PNG
rename to docs/sections/services/mapper/flow.png