Merge remote-tracking branch 'origin/develop' into breaking

docs/examples/blind-auction.rst

@@ -24,6 +24,7 @@ to receive their money - contracts cannot activate themselves.
 
 ::
 
+    // SPDX-License-Identifier: GPL-3.0
     pragma solidity >=0.5.0 <0.8.0;
 
     contract SimpleAuction {
@@ -184,6 +185,7 @@ invalid bids.
 
 ::
 
+    // SPDX-License-Identifier: GPL-3.0
     pragma solidity >=0.5.0 <0.8.0;
 
     contract BlindAuction {

docs/examples/micropayment.rst

@@ -142,6 +142,7 @@ The full contract
 
 ::
 
+    // SPDX-License-Identifier: GPL-3.0
     pragma solidity >=0.4.24 <0.8.0;
 
     contract ReceiverPays {
@@ -338,6 +339,7 @@ The full contract
 
 ::
 
+    // SPDX-License-Identifier: GPL-3.0
     pragma solidity >=0.5.0 <0.8.0;
 
     contract SimplePaymentChannel {

docs/examples/modular.rst

@@ -19,6 +19,7 @@ and the sum of all balances is an invariant across the lifetime of the contract.
 
 ::
 
+    // SPDX-License-Identifier: GPL-3.0
     pragma solidity >=0.5.0 <0.8.0;
 
     library Balances {

docs/examples/safe-remote.rst

@@ -25,6 +25,7 @@ you can use state machine-like constructs inside a contract.
 
 ::
 
+    // SPDX-License-Identifier: GPL-3.0
     pragma solidity >=0.5.0 <0.8.0;
 
     contract Purchase {

docs/examples/voting.rst

@@ -32,6 +32,7 @@ of votes.
 
 ::
 
+    // SPDX-License-Identifier: GPL-3.0
     pragma solidity >=0.4.22 <0.8.0;
 
     /// @title Voting with delegation.