Return gasPrice at gettxinfo API's method

apps/block_scout_web/lib/block_scout_web/etherscan.ex

@@ -440,6 +440,7 @@ defmodule BlockScoutWeb.Etherscan do
       "from" => "0x000000000000000000000000000000000000000c",
       "gasLimit" => "91966",
       "gasUsed" => "95123",
+      "gasPrice" => "100000",
       "hash" => "0x0000000000000000000000000000000000000000000000000000000000000004",
       "input" => "0x04",
       "logs" => [
@@ -986,6 +987,7 @@ defmodule BlockScoutWeb.Etherscan do
       input: @input_type,
       gasLimit: @wei_type,
       gasUsed: @gas_type,
+      gasPrice: @wei_type,
       logs: %{
         type: "array",
         array_type: @logs_details

apps/block_scout_web/lib/block_scout_web/views/api/rpc/transaction_view.ex

@@ -68,6 +68,7 @@ defmodule BlockScoutWeb.API.RPC.TransactionView do
       "input" => "#{transaction.input}",
       "gasLimit" => "#{transaction.gas}",
       "gasUsed" => "#{transaction.gas_used}",
+      "gasPrice" => "#{transaction.gas_price.value}",
       "logs" => Enum.map(logs, &prepare_log/1),
       "next_page_params" => next_page_params
     }

apps/block_scout_web/test/block_scout_web/controllers/api/rpc/transaction_controller_test.exs

@@ -456,6 +456,7 @@ defmodule BlockScoutWeb.API.RPC.TransactionControllerTest do
         "input" => "#{transaction.input}",
         "gasLimit" => "#{transaction.gas}",
         "gasUsed" => "#{transaction.gas_used}",
+        "gasPrice" => "#{transaction.gas_price.value}",
         "logs" => [
           %{
             "address" => "#{address.hash}",